Either way, if a movie is stuck in it, you take it apart and reclaim your movie. And yes, that "curtain" on the slot load keeps it as clean as a tray would. In fact, if the DVD has a little dust, the curtain will remove some of the dust, whereas the tray will just throw the crap everywhere on the inside.
I like the slot...just because it's more convenient and looks much nicer.
If I don't get my 90THz AMD Quadraplex system soon, I'm afraid I may just combust right here.