iMac

Thinking about getting an iMac but need some clarification on iMovie. Is there any limit as far as how long of a projet/video it can save/render? Like can it make a 1hr + movie from my camcorder? That leads me to my next question.. the camcorder is a Sony HDR-HC3, I think it saves in .mts format, will iMovie import these with no issues? I don't want to have to convert files to get them into iMovie. And lastly will exporting/rendering from iMovie to bluray format work? Can you burn to bluray discs the finished product?

thanks in advance..