Although we have been discussing our views on different forums, here is a summary of my personal experience with 3 so far.
Please note that the events are listed in chronological order but I am not able to recall the exact dates etc. Also, I have numbered each item so that you can ask me for any clarification, if needed.

1. Could not find Motorola A830 anywhere. Wanted it because I have used Moto before (Timeport) & really liked it.
2. Finally got the phone and was connected within an hour.
3. Was so happy that I almost instantly decided to port my number in, which I have owned for over 5 years.
4. Voice calls kept on dropping: broken voice during a conversation; at the end, I could hear the caller, but they could not and finally cut me off.
5. Tried to contact 3 over the phone. The number was at 0870 (national) rate - around 8p/minute, costing me nearly 3 quid for the 35 minutes I spent waiting.
   Finally got through to India and the lady did not have a clue about a possible solution.
6. Found the customer services address and sent an email. Got a reply in two days.
7. However, they promised to look into the problem and let me know either by phone or email. Never received a reply.
8. Also, had to ring them several times before my number was ported in. At times, there wasn't even a mention of a request I had previously made.
9. Porting in my number was a big mistake. All my friends and family kept on trying to contact me but couldn't - the calls kept on dropping and at times they were redirected straight to my voicemail.
10. Tried to find an option to switch voicemail off - no such option available, said the 3 customer services.
11. Tried to tag along, hoping things would get better. However, decided to port my number out to someone more reliable.
12. Received a PAK code to port out, but after 3 phone calls.
13. Took my phone to CarPhoneWarehouse where I bought it from, hoping to get an exchange. I believed that maybe the handset was faulty enough to contribute to dropping and non-connection of calls. The staff was really helpful and finally found a branch in my local area (albeit 10 miles away) which had a handset available for exchange.
14. The branch manager attempted to make the swap but the computer did not let him. Eventually he contacted 3 and was told that only 3 could do a swap - not anyone else!
15. I was really annoyed to hear that - 3 can't sort their own mess themselves and would not let anyone else to make an attempt either!
16. After a good few phone calls, got a date for exchanging the phone.
17. In the meantime, downloaded a few video clips from the Internet. A clip of approximately 1 mb took just a few seconds to come to my handset - amazing!
18. Got a brand new A830 and gave the old one with the packaging, accessories, etc. to the delivery guy.
19. Inserted my 3 chip, tried to take a photo and guess what; got a black screen.
20. Tried to play videos stored on my SD card, but again, a black screen with the sound playing in the background.
21. The still photos, however, both on the phone as well as on the SD card were fine although they did not seem to be as sharp as they appeared in the previous handset.
22. Sent an email to 3 and guess what? I received a phone call within 30 minutes of sending the email regarding another exchange of the handset.
23. Was really impressed and am waiting for the new set to arrive.
24. Got the replacement phone but guess what?
25. Same quality of voice calls and convesations ending abruptly.
26. It's been so many months now but whenever I try to take my A830 out of my closet and make a phone call, it seems like nothing has changed.