I have had my sony k770i for about 5 months so far. I bought my fiance one for his birthday. He loved it from the word go and I was jealous that he got a new phone that was better than mine and seeing as my old samsung died on me a few weeks before my birthday he decided to get me this sony (to match his!!). Only I have the pink version!
I have never had a sony before. In the past few years I have stuck with Samsungs (my last being a pink U600). Only I was bored with them and hated the battery life!
What can I say? I like this phone.
+ I like the look of it - its nothing special but i like the pink colour and i like the size of the screen which is also of good quality. The buttons are quite small but easy to press. I like the fact that you can cover the camera lens when not in use by the slide feature on the back.
+ The menus are easy to navigate, simple to use and easy to understand.
+ The camera on this phone is great. It is only a 3.2 mp but being sony i guess you would expect quality and in the daylight this phone is fab. However in dimly lit areas the quality lacks a bit. But what do you expect from a phone camera? The video is okay although nothing special.
+ Love the mp3 player - sound quality is great. Again being sony you would expect this. Easy to navigate and find tracks. Also has fm radio built in.
+ Love the 'Task Bar' menu - this allows you to put your favourite/most used applications/programs/options onto a simple menu which enables you to get to where you want to go quciker. Eg. on mine I have text message and also internet and alarms.
+internet is good, better than my samsung and fairly quick.
+Love the fact that the bluetooth can act as a modem for my laptops internet - this can be handy although it is quite slow!
+ Amazing battery life. I get 7 days without charging and I use my phone a lot.
Afraid I cant comment on the games, there are a few on here but I dont use them.
+ Love the fact that theres a number of different alarms you can set without losing your current set ones. And the fact that you can customize the name, sound and even have a picture flash up when it goes off!

And for the things i dont like...
- Dont like the fact that vodafone has put certain pictures and wallpapers on the phone that i cant delete
- Dont like the sony songs that i also cannot delete
- Not much memory - however you can buy sony memory cards
- dont like the fact that it says vodafone on the front and on the menu for the internet. (I unlocked my phone - i wanted pink one and could only get it on vodafone - so i am not on vodafone).

Not a lot I am unhappy with.
I miss the slide feature or flip feature I used to have with the samsungs but this is personal preference.

To anyone wanting to buy a really great high spec phone on a small budget I would recommend...although if you update regularly perhaps you should be looking at something newer - this phone has been around for a couple of years now and lets face it - the phone market is going up and up and up! Applications is the next big thing and unfortunately this phone cannot use these.