All FWIW...

Going from 29.97 to 25 or 24 fps you've got less pictures, so any transitions are not going to be as smooth, no matter how you do it, though an awful lot depends on what you're used to and what equipment is doing the display.

Once you're used to NTSC, a lot of folks find fault with PAL because of it's lower frame rate. And running 24 or 25 fps to a NTSC TV monitor isn't going to look great, or otherwise why go to the bother of telicine with film.

RE: quality, you're going to suffer some from the conversion of the image itself, but perhaps you might minimize this in some situations by cropping the video to the correct aspect ratios and then enlarging by an even amount (say 10%?).

As far as the frame rate conversion goes, maybe it would help (at least) during problem scenes (panning etc.) to add a bit of motion blur with supersampling? When we look at film, what sets it appart from DV is the softness and often some motion blur - if an object moves across the screen in 24 frames vs 30, there will be more blur just because you're taking fewer time slices, and each slice (frame) will by neccesity contain more motion.