Usually I do the actual presentation using Adobe Acrobat Reader, although it has lots of nasty bugs. Next time I may try pspresent. A quick try indicates that it works well and has nicer-looking output than acroread. It does double-buffering, so moving through the slides in the usual order works smoothly, but the one flaw seems to be that it's slow to flick through a whole sequence of slides (as one might do to go back to an earlier part of the presentation to answer a question). But you can specify a slide number to jump to (type the number then ENTER), or bypass overlays when changing slide (by holding shift).

Preventing ps2pdf from making PDFs with JPEG-compressed images

Pass the following options to ps2pdf: -dAutoFilterColorImages=false -sColorImageFilter=FlateEncode

This tells it not to guess what type of image compression to use (which in effect means use JPEG for colour images without indexed colours), but to always use ZIP-style (lossless) compression.

The full list of parameters you can pass to ps2pdf is documented here. To use them with ps2pdf, use -sOptionName=string for ones which take strings, or -dOptionName={true|false} for logical flags (see here).