Have a look
http://www.pocketgpsworld.com/ and have a read of the forums.
Tom Tom has not been without it's problems! Although I have a wired PDA type. Don't subscribe to Tom Tom's camera database it is an expensive rip off.
The speed camera database at pocketgps is far cheaper and probably more upto date.
Legally the speed camera database is not a problem as it is not a detctor, those are illegal.
I believe the speed camera database can be installed on a TT 700.
see here