I have been using this phone for about a month now and it certainly is very tough. I am a Paramedic and outdoor enthusiast, so my phone gets abused. No matter what I have put it through it is as prisitine as the day I unboxed it.
You shouldn't buy this phone if you want top-of-the-line features.
It's not going to win any techy awards. That being said, it does have some decent functions.
Phone - good reception, good battery life, nice loud ringer, good sound on calls, excellent speakerphone, bright display and back-lit keypad.
1.3 Megapixel Camera - decent pictures, but no flash.
Radio - Great reception & sound quality.
MP3 Player - nicely laid out, easy to use. I have an 8GB MicroSD full of tunes and it does really well.
Flashlight with dedicated button -- probably my favourite feature. It is surprisingly bright but has come on twice in my pocket when I forgot to lock the kaypad.
Email - not great for replying, of course, but you can tell it how often to check your emails and have them download to your phone -- or just the headers.
THE NOT SO GOOD:
Speed dial bug: despite having dad's mobile stored as speed dial 2, when you press speed dial 2 the phone seems to randomly pick which number of dad's to call. Sometimes home. Sometimes work. Sometimes mobile. Waiting to hear from Samsung for a fix.
WAP broswer - it's just rubbish. Very slow and almost impossible to use. Despite my 8gb card, get out of memory errors all the time.
Games - don't bother. It will take java apps and games but I have yet to find a good one that works. Did get google talk working on it, but it's very difficult to txt-chat.
Customization - it has an option to edit your own coulour profile but it is very limited, I haven't tried the Samsung PC software because I'm a MAC/Linux user, but that may have more options.
Again, this isn't a phone for people who like to "trick out" their phones. As a phone it is excellent. The radio, mp3 player, flashlight, and email are handy additions to make life a bit easier but aren't out to compete with the top-of-the-line phones out there. However, immerse one of those phones in a puddle of bloody vomit for 10 minutes and see if it still works after a rinse under the tap. The B2100 does.