I would say v180, because I don't like any useless extras (like camera). Just calling and sending sms. Only extra is mp3-ringtones. That's good because I don't think that anyone else has intro of bleach-anime as ringtone Unique ringtones ^_^
I have used a 180, 220, 400 and a 551 . the 180 is great if you just want a phone, the 220 has better recption than the 400 Its basicly a 180 with a camera but the parts don't interchange. the 400 has a bigger screen that the other two but the reception seems have problems in my area verses the other two . the camera is better than the 220. The 551 is a step above all the others. better reception, much better camera .video, I like the button configuration. you can add skins to change the screens . With the 8.18 software that came out in april all the bugs are fixed. you have edge technology for broadband speeds with the internet and bluetooth for wireless headsets and file downloads /uploads.you can upload rintones, mp3'ringtones with all of the above,and pics .