For simple manual stepping, etc. debugger speed is probably not that important. Have you ever tried to really use watchpoints? Given up after your program slowed to a crawl?

We had a debugger that could run many watchpoints at almost full program speed some time ago, see http://www.netilium.org/~mad/dtj/DTJ/DTJK07/ for details. The key point is that Parasight was fast enough to make tools like this useable.

I wish it had been here before I finally succumbed to curiosity and bought this piece of junk. It's really, truly awful. The worst excuse for a book I've bought in quite a while -- and I buy a lot of books.

Well now we know who had better be one of the first layoffs. If they keep this moron around it says a lot about the future of Microsoft.