Someone else mentioned most of the interface weirdnesses. I don't really like having separate (VB-like) code windows. They Web-bed out the Help system so half the time I just go back to 97 to find help on certain topics. It seems to bomb out a lot more. Plus all osrts of junk doesn't work anymore and I haven't used it enough to figure out what to use instead.
Blech. Every other version of Access bites. I remember for Access 95 there were 3rd parties who would post on their web sites that they couldn't get their products to work with Access 95. So who knows, maybe the next iteration is better.