Slicehost is a Xen-based VPS, not dedicated. The difference between them and other VPS providers is that they do not oversell each box so you get a good price/performance ratio.

I'm still on the waiting list for slicehost. Is this common or am I doing something wrong.

This is common. I've heard that some are waiting many weeks (or even months) to be granted a slice. The slicehost folks have recently introduced an option to prepay for your slice, bumping you up the queue.

I was lucky to get a slice the moment I signed up for it (early adopter I suppose). I have been very happy with their service.