Indeed. I use it extensively on my HTC P4550, and it's showing it's age. If I am reading something, and I get a text message or an email that I have to respond to right away, it's often easier to close the program, and open it up again when I'm done. Otherwise it slows to a crawl for the next five minutes. In the mobile version, there's no way to skip to a page. So, the other day when I installed a new ROM, I forgot to see if there were any registry keys that held page locations. I ended up having to sit there for ten minutes with my finger on the 'next' button.
I pestered Bill Hill about the future of MS Reader on his blog and he indicated that the team is still around, but didn't offer much more than that. I figure if somebody at Microsoft doesn't want to comment, then that usually means that there are plans of some kind.