All domestic market camcorders record at a frame rate relative to the TV system of the country they are designed for. If you have a PAL camcorder it will record at 25 fps - if you have a NTSC camcorder it will record at 29.97 fps - on a domestic mark...
Depends on the features you need. Make sure it's BRAND new, Sony is about to bring out the new stuff, although your numbers seem somewhat new to me! We still sell the DVD105.
Specification wise, the US model DCR-DVD308 is the same as the DCR-DVD708: Hopefully, the owners manual for the DVD308 will also apply to the DVD708 - you can download it here: