if you say its poor- its because composite video isnt that great. not adaptor.
adaptor is actually really quite good for for $20.
you simply cannot do presentations with composite video - of course it looks poor compared with vga monitors - the resolution of composite video is barely 384x288 at the best... most tv technology things have only 250 lines of resolution. compared to at least 1024 on vga.
you want to do powerpoint on a laptop - strongly suggest you try using keynote to convert powerpoint to a quicktime movie- then play movie.
there are no good composite video solutions... for doing this.