Since I've been using an iphone for 2 years and bb not even 2 days, you're more than welcome to add anything I miss out here.
Performance: generally, iphone does better in high-capability performance. (i havnt seen any bb doing high performance app yet) one of those being very interesting futuristic type of app called 'augmented reaility'. Besides, gaming on 3gs can still go extremely far beyond what current games are offering. I think in half a year, there will probably be games like mini-counter strike playable on 3gs (multiplayer-able, of course).
Applications: iphone offers loads more apps that can be downloaded via itune (or crack version somewhere else **NOTE: im not sure if contract iphone can install crack app or not** However, the apps on each phone are pretty different in function and therefore depends on one's personality and/or purpose of usage.
Internet/Social network: Althought both phones can surf internet with ease, i have to admit that using the trackball as a mouse still feel kinda slow compare to iphone's touchscreen. What bb packed inside however is the push mail system that allows whether it be bb message, facebook notification, twitter update to pop up instantly so u can do everything social-network-ish always in real time. This can be as addictive as when you first try msn where you cant stop chatting with friends even if all the things ur saying are 'lol' and 'yea'.
Keyboard: I'd have to say this is up to each person because iphone's virtual keyboard can be hard to use at first and still hard to use later (or not) depending on one's texting professionality. bb's keyboard, of course, is a rock solid keyboard. With both hands on you can type 'The quick brown fox jumps over the lazy dog.' within 15 secs. Thai keyboard, however, takes longer time to familiarize with due to only 3 rows of keyboard and no thai alphabet whatsoever on it.
System: From my 2 days with bb, one of the fondest i discovered using it is that multiple applications can run simultaneously. You can surf the net, switch to type a message, go and listen to some music, coming back to the browser to find that its done loading. On the iphone, this would be very frustrating sometimes when ur using an app and some1 calls and you have to restart everything over again.
Camera/earphone: on 3gs vs bbbold, the camera quality are kinda the same. bold wins with integrated flash. iphone's earphone simply sucks because any typical earphone just cant fit with its socket requiring you to buy its own earphone. Video taking comes with 3gs only (not sure about 3g) Bold has video taking app built in.
Price: currently 3G and bold has the same price. 3GS being more expensive buy around 4000 baht.
Other factors to be considered include battery life, and i totally forgot to mention that with blackberry, you'll get to be inside the bb society, exchanging pins and u know chatting all the time from anywhere in the world.
well, if you ask me which one to choose, i'd say it's totally up 2 your personality. I chose bb because I spent enough time with iphone already, just wanna try smthn new. Btw, my pin is 2127C7F6. add me ... or buy one and add me. LOL
