You can also download Mini Opera on the A630 which would give you full webpage access....(if you have the 5.99 tzones plan it will work). The Sidekick and the A630 are COMPLETELY different phones/aim/text units. It all depends on what you want...
I have used the A630 and a co-working uses a Sidekick 2 and I have played with it alot.
Depends on what you want. The Moto A630 is WAY smaller than the Sidekick...it is more of a phone w/qwerty and the Sidekick is well a Sidekick. If you are going to be doing alot of web browsing then go with the Sidekick...bigger screen so it will load more of the webpage and be easier on the eyes. The Sidekick is a closed end platform and you can't really do much yourself (yes if you have a Devkey and know Java then you can do things yourself but not as easy). If you want your own Mp3 ringtones that you can add and delete on the fly and not worry about paying for it then the Sidekick WILL not do it. You have to download ringers from T-Mobile. (Cost money compared to the A630 that you can use any mp3). If you have used or know anyone with any Vxxx (V300,V400,V600,V551,V3,etc) then you can play with that and know how the menu system and whatnot goes because it is the same phone but with the screen tilted the other way. Vxxx screen size (176x220) A630 (220x176). You can also get various java games (mostly free if you look) that are Vxxx compatible that will work on the A630 and away you go with games. The Sidekick comes with games I believe but if you want to get them then you have to pay to download them
AIM on the A630 uses Text Messages so you need a text messaging package. (I am pretty sure that it uses text messages and not wap access...Kinda long ago and so many phones ago). It is pretty good with AIM just depends on how much of a user you are...Heavy or not that heavy. The Sidekick seems to work alittle bit better with AIM but like I said earlier the Sidekick is for web/aim...and the A630 was originally a phone w/qwerty AIM, web.
Sidekick is HUGE compared to the A630, A630 has bluetooth which is a plus for sending files and using a headset. Sidekick would be awesome if it had bluetooth but it doesn't and I don't know if it will ever happen.
Prices:
Sidekick...29.99 without a voice plan gives you unlimited data and unlimited text (also AIM). With a added voice plan 20.00 on top of plan (includes the same 29.99 but includes whatever voice min.)
A630....price of voice plan +14.99 text+5.99 tzones. Includes data and unlimited text (also AIM). It also includes unlimited picture messages
All comes down to about the same price but just different devices. All really boils down to what you like and what you would need. The A630 also has a regular keypad on the outside of the phone that you can answer text messages from so you don't have to open the phone all the time. Plus you can see who is calling. With the Sidekick you have to flip the screen open all the time to reply to messages.
Phone quality I can't really compare the two because I haven't used the Sidekick for voice just data. But I would imagine they would be pretty comparable just depends on if your a headset person or not. The Sidekick has a standard headset jack and the A630 doesn't only bluetooth. I believe you can find a adapter that plugs in the bottom and you can use a regular headset but not sure.
If you have any more questions I would be happy to answer them for you.