I've been using an HTC One for about a month now and if I had to do it over again I would not switch. In a nutshell, each has it's advantages and disadvantages and I don't think either one is that much better to be worth the hassle of changing. For that reason I would not recommend to someone that is comfortable with Android make the switch to an iPhone either.
The main reason I switched was for the larger screen and the HTC One screen is definitely superior to the screen on my iPhone 4. But, for that added screen real estate I had to give up one handed use, and I'm not sure I'm happy with that trade. I used the iPhone without a case. I use a case with the One, not for protection, but to make it easier to grip. I also miss the home button on the iPhone, it's more inconvenient to reach up and get to the power button on the One. I also found the buttons on the iPhone easier to access/press, yet at the same time less likely to press accidentally.
My biggest complaint about iOS on the iPhone was the hassle of having to dig down a couple of menus to turn bluetooth on and off. It looks like Apple is fixing that in iOS 7, so that will no longer be an issue. I installed Power Toggles on my One and that definitely helps, but I never worried about turning wifi or gps off on the iPhone because the battery life was so good. Battery life has been good for me on the One, not as good as the iPhone 4, but I haven't had any problems making it through the day.
My other annoyances with iOS have to do with way iOS handles files and photo management. But since I use my iPad mostly for those tasks, they are not that much of a bother on the iPhone.
One of the big advantages of Android is the ability to customize everything. This is also a curse as well because it can require some digging to find apps to do what you want and also predicting how they will interact with each other. For me, this ability to customize was not really an advantage. Much of this customization is geared towards how your home screens look. To me, I don't really care how my home screen looks, I'm just interested in getting to an app as fast as possible, and I think both phones are equal in that regard. Much is made of widgets, but I just haven't seen any that are essential. It seems like the 2 most popular widgets are calendar widgets and weather widgets. Personally, I know what my events are for today, I need a calendar app to view future events, so you need to open the app anyway. Likewise with weather, I'm more interested in the forecast than current weather, so again you're better off opening the full app.
My other complaint about Android is although most iPhone apps have Android equivalents, there are a few that I have not been able to find suitable replacements for. One advantage of Android is that there seems to be more decent free or low cost apps than there are for iOS.
One thing I like about Android is the tight integration with Google since we're a Google shop at work. Gmail is better on the One, but it is very good on iOs as well, so that's not a big advantage. I do not like the native calendar apps on either the iPhone or the One. So I used Calengoo on the iPhone and aCalendar on the One. aCalendar is far superior, I found Calengoo to be very laggy as you had to wait for it to sync every time you opened it up. Also, viewing a calendar on the One's larger screen is much more helpful. Likewise with tasks, I wanted something that synced with Google tasks. The default tasks app does on the One, but I didn't like it and installed one called Tasks. I find it superior to GeeTasks which I was using on the iPhone.
At first I was disappointed in the default keyboard on the One. I thought because it was larger I would be able to type easier than on the iPhone. But, for some reason that was not the case. However, I installed Swiftkey and am very happy with my typing experience.
Will I return to the iPhone? Not with their current lineup. I had the iPhone 5 for a while and returned it because of wifi problems. If a new iPhone comes out, even an iPhone 5s, that corrects these problems, I may. Although by that time I may be so used to my One that it won't be worth the effort.
The main reason I switched was for the larger screen and the HTC One screen is definitely superior to the screen on my iPhone 4. But, for that added screen real estate I had to give up one handed use, and I'm not sure I'm happy with that trade. I used the iPhone without a case. I use a case with the One, not for protection, but to make it easier to grip. I also miss the home button on the iPhone, it's more inconvenient to reach up and get to the power button on the One. I also found the buttons on the iPhone easier to access/press, yet at the same time less likely to press accidentally.
My biggest complaint about iOS on the iPhone was the hassle of having to dig down a couple of menus to turn bluetooth on and off. It looks like Apple is fixing that in iOS 7, so that will no longer be an issue. I installed Power Toggles on my One and that definitely helps, but I never worried about turning wifi or gps off on the iPhone because the battery life was so good. Battery life has been good for me on the One, not as good as the iPhone 4, but I haven't had any problems making it through the day.
My other annoyances with iOS have to do with way iOS handles files and photo management. But since I use my iPad mostly for those tasks, they are not that much of a bother on the iPhone.
One of the big advantages of Android is the ability to customize everything. This is also a curse as well because it can require some digging to find apps to do what you want and also predicting how they will interact with each other. For me, this ability to customize was not really an advantage. Much of this customization is geared towards how your home screens look. To me, I don't really care how my home screen looks, I'm just interested in getting to an app as fast as possible, and I think both phones are equal in that regard. Much is made of widgets, but I just haven't seen any that are essential. It seems like the 2 most popular widgets are calendar widgets and weather widgets. Personally, I know what my events are for today, I need a calendar app to view future events, so you need to open the app anyway. Likewise with weather, I'm more interested in the forecast than current weather, so again you're better off opening the full app.
My other complaint about Android is although most iPhone apps have Android equivalents, there are a few that I have not been able to find suitable replacements for. One advantage of Android is that there seems to be more decent free or low cost apps than there are for iOS.
One thing I like about Android is the tight integration with Google since we're a Google shop at work. Gmail is better on the One, but it is very good on iOs as well, so that's not a big advantage. I do not like the native calendar apps on either the iPhone or the One. So I used Calengoo on the iPhone and aCalendar on the One. aCalendar is far superior, I found Calengoo to be very laggy as you had to wait for it to sync every time you opened it up. Also, viewing a calendar on the One's larger screen is much more helpful. Likewise with tasks, I wanted something that synced with Google tasks. The default tasks app does on the One, but I didn't like it and installed one called Tasks. I find it superior to GeeTasks which I was using on the iPhone.
At first I was disappointed in the default keyboard on the One. I thought because it was larger I would be able to type easier than on the iPhone. But, for some reason that was not the case. However, I installed Swiftkey and am very happy with my typing experience.
Will I return to the iPhone? Not with their current lineup. I had the iPhone 5 for a while and returned it because of wifi problems. If a new iPhone comes out, even an iPhone 5s, that corrects these problems, I may. Although by that time I may be so used to my One that it won't be worth the effort.