This phone has been great for over the time I have had it. I have only every had one hardware problem with it and that was the battery needed changing as it wore out too quickly!

Sound: The speaker - I think - is great. It is very loud and when I play music out loud sometimes it comes out crystal clear not like some other rubbish phones that sound so crackly and just plain awful!
Screen: The screen is clear and bright however I do recommend getting a screen protector for it as it does scratch easily. One thing I would say is that even though I have mine set to the lowest brightness setting it is still very bright to look at. This has its advantages like when you are outside where it is bright you can still see the screen but at night if you look at your phone sometimes you do get briefly blinded by it. But maybe that is just me!
Touchscreen: The touchscreen element itself is not as responsive as iphones or similar smartphones but to be honest I think it just takes some getting used to as I can use it just fine.
Navigation / Menus: The navigation of the phone is easy to understand and you can drag and drop special widgets on the home screen. On unlocked versions of the phone you can remove your phone network from the screen and this is great because then you can see your background in full. This is definitely a big plus from me!
Internet: To be honest I don't bother using the internet on the phone. It does work but it is way too slow for my liking and even then the response is rather poor, not to mention it drains battery life like mad. To be honest I wouldn't recommend this phone if you want to browse the internet.
Camera: The camera is 3.5mp and this is great for a phone like this. You can have various camera effects and personally I use the "fluorescent" option as I think this makes the photos come out with much nicer colouring to them. The videoing function is not up to much and I don't really use this.
Calling/Text messaging: I never have any problems when using it to call people, I always get clear reception. However, battery life gets drained quickly when using the phone for calling. Texting is easy and works well too.
Storage: I would certainly say you need a memory card for this phone as you cannot store much at all on its internal storage. I have a 4gb memory card and it has lasted me all of this time and is nowhere near half full.