There are many things to like about the phone, but here are some notable complaints from my own experience:
-My biggest complaint is the lag which occurs here and there. It's not often, but it's enough to be noticeable and once in a while frustrating. The phone will sort of "hiccup" when you try to do something you haven't done in a long time (guessing this is where the partitioning of memory comes into play). Hoping the 2.2 Froyo update will curb this [minor, but frustrating] issue.
-Battery life. This isn't so much a complaint as it is just noting, since phones of these kinds have similar average battery life. It's just a little frustrating having a phone that offers such a vibrant screen, all these live-updating widgets, live wallpapers, tools to use (GPS, WiFi, etc), only to find you have to use them very sparingly or have them set to the lowest setting or longest update intervals, in order to conserve batteries. Yes, this is the battery technology we live with given the power consumption of these phones, but you still can't help but feel "cheated" from using your phone to its fullest potential. I never feel at ease throughout the day, especially if I have a long day without access to a charger.
-While there are some amazing advantages to using Android, the OS is not without faults (this is true for all other OS' too, of course). Some things are just bizarre - like inability to customize calender alert tones, sometimes the system lags, etc. Granted, I've tried Blackberry and iOS, and Android is still my favorite. Android, in many ways, is a blank slate, and requires work to make the phone an optimal and personal experience. There's just still room for improvement.
-Keyboard. This is an extension of my last complaint about Android OS. The keyboard lags, misses obvious auto corrections, and just doesn't seem as responsive as say the iphone's. On the iphone, I type with utter confidence, knowing their auto correction will almost always get the word I want, that there will be no lag in the multi-touch, and for whatever reason, I just don't miss keys when typing on the iphone. None of this is true with the Android stock keyboard. After research, I've found Smart Pro Keyboard is superior to stock Android, and mirrors the experience on the iphone a little more, but still doesn't match up. Once again, it's one of those things that requires work - finding the right keyboard, adding custom corrections, etc. And once again, I'm hoping Froyo fixes some of these lag issues. It can sometimes be frustrating thumbing out long messages/emails.
-Four bottom capacity keys: Let's face it, sometimes they just don't respond, or respond very slowly. Is it Android, is it the hardware? I don't know, but it can be annoying.
-While I think the phone looks nice, and the thin form is excellent in my pocket (love the little bump on the back/bottom too. Really helps with taking the phone out of pocket), I dislike it when people mistaken it for an iphone 3G/3GS. Minor complaint, and understandable mistake. Wish Samsung was more daring with their design for Tmo. I actually love how the front of the Captivate looks (not so much the back, though).
Some other very minor complaints:
-Lack of flash. No two ways about it. This sucks. Night mode doesn't suffice.
-Power button on the right takes getting used to.
-Speaker is VERY weak and low during phone calls. It seems to play music loud enough, but for whatever reason, voice calls are low.
-Vibration is also very weak. When in my pocket, I almost never feel it.
-No LED indicator. Just something to get used to.
That's all I can think of for now. Don't mistaken this post for disliking my phone. I actually really like my Vibrant. These are just issues, if resolved, would make it ideal.
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