Yes, the selphy 750 will be fine as it have an optional battery pack.
Just be aware that the battery is not included and that the prints are more expensive than traditional prints.
But now, as I consider those printer as discardable (at least when I take them on vacation in very dusty places) I tend to buy the cheapest model I can find as long as it's possible to attach the battery.
I've had CP300, CP600, CP740, and CP750... I don't really see big difference between them so I tend to search for cheap old model on EBay a few week before leaving and if I can't find one, well I still could just go to the store.
I always use USB cable because I don't want to remove the card from my camera, I don't care for the LCD or retouch options in the printer as I have more options with my camera. The only thing that I could think as usefull is the integrated USB cable (my CP600 didn't have one, so as I tend to always forgot things, one day I wasn't able to give a promised print because I forgot that damn cable. But if you're from the carefull guy type it's no problem).
The quality from those little printer is really great and as the resolution is low it can hide some image quality problem (I've printed a lot of pictures to discover after that I got a problem with my lens and that most where out of focus but taht was no noticable on the prints)
But the real bonus is that the print have a final protective layer that's water and tear proof and the back is like a poscard. It always fun to ask people to try to tear the small side of the print (that you can detach). The trick is to use fingernails and go for the side with serrations
Speaking of polaroid something was funny, most of the times when I gave a print people where just waving them just like a polaroid and it's true that everytime I met polaroid shooters they where highly interested in the printer.
Here's some sample of my printer in use
http://rapidshare.com/files/194415804/cambodge.rar
So yes, definitely take it on vacation especialy if you go out of the big cities it was really the best idea I got for my travels. It's like a little touch of magic especially with the children and when they saw the (pretty ugly) yellow print transforming in colorfull prints.