About the mini dvd discs, it all depends on what type. There are +r and -r, +rw and -rw, as well as dvd ram discs. It will depend on what dvd player you are using, however if it isnt a rw or ram disc, you will have to finalize it, just like burning a disc, before you can play it.
If you are going to go that way, go with a camera that will support ram discs. They are rewritable and they are random access memory discs, do you know what that is?
For those who dont here is a quick explination. Cds and dvds are like records, the information is recorded in tracks, like records. Does that make sense, hard to explain it without a visual. But anyway, if you scratch the disc, you are pretty much screwed becuase you wont be able to record anymore (rw) or to play it. But with ram discs, it will record in the next available spot if there is anything wrong with the disc, it will jump to an open area to record.
I hope that makes sense, I have always understood it, but I have trouble explainig it.
As for dvd playback, it can be tricky with all the different models cameras, players and discs and unfortunatly, sales people really just want to make a sale, and usually dont know if it will work or not with your set up. I have seen it and I would always say to people that there are so many factors it is really hard to be sure.
Rich, I think you really just need to decide what you want to use this camera for, and think about what you might want to use it for and decide from there. Do you think you would be playing the mini dvds a lot in your dvd player or is that something you might like to have just in case. Or are you usually going to upload the video and edit it first before finishing it for play back. Is this for family, business (corns), expos. Same with options, like 16:9 and 5.1 audio, they are good to have but are they essential to what you want to do? There is a lot to think about, do you know anyone with a camera that would let you borrow it to try it. It would be kinda like buying a cheep one untill you know what you want, but you dont have to pay for it!
Or, I know in Canada, Walmart has a really good return policy, if it is the same there, you could buy one and try it out and return it before you make a decision. Try out a few models, you might just have to go to different stores though...