I switched to the iPhone 5 when it came out, and now that my time is up, came back to Android for the Nexus 6. iPhone was not for me, and I'm a big Mac user.
Problems I've run into so far:
1. Random shut down/restarts, often while on the phone.
This happen to me once. I figure it was my brand new case.
2. Sometimes it won't respond when I try to answer the phone, which leads to missed calls.
I can see that happening. I hear it ring, but it doesnt come on to answer.
3. When trying to answer the phone, and it won't answer, I lose the notification and have to fight my way back to the phone app.
4. Sound is iffy. Sometimes it rings, sometimes it's staticy, sometimes sound starts way late.
This happens alot. Its like something is fighting the audio channels for space.
5. Camera app stinks, but that's an app issue, I guess. I just downloaded another.
6. Camera is dark in hangouts. Fine in other apps, though.
7. Laggy camera.
8. Button placement on the side is awful. I keep restarting my phone.
9. Notification sounds even when sound is off, and I'm not using the notification/priority settings--just volume. WHY? I understand the idea behind the notification settings, and I like it. But if I simply use the volume button, that should just turn off all sound. If I need to not have notifications or just priority notifications, I will use notifications to control it. Otherwise, please continue to show the notification on my screen for crying out loud! Just make the phone silent when I turn the volume down. (Watch, because I got indignant, I'll find out I'm just doing it wrong. heh.)
10. Notifications don't always respond. I tap it, and it just hangs there.
this as well...
It seems to me that most of these are problems that will likely get addressed with updates, so I'm not freaking out yet. I haven't run into anything that I really just hate like I did with the iPhone. As far as I can tell after using the phone for a couple weeks now, any other issues I have are just issues from adjusting to the operating system again. I ordered a case that I'm hoping will alleviate the button problem, since that's a done deal--no fix coming for that.
That's all I can think of right now. I did a factory reset, so we'll see if that changes anything. I haven't received 5.0.1 yet.