For me, I can no longer use 98 since I dabble with video editing and the file sizes exceed 4GB. That item alone makes the DOS based OSes ones that I can't use.
But for many 98 will continue to be usable for many years.
It's may advice that people learn how to install 98. It's not that hard once you collect the drivers for your machine.
There are other limits in the DOS based windows, but my choice not to duplicate such discussions but note which one item was the killer item.
I'm getting ready to have 98 reinstalled. I find myself wondering if I would gain very much by switching to XP at this opportune time. I guess asking which would be better for me may be a little like asking what car is better, i.e., like beauty,it's in the eyes of the beholder. But still if anyone has any thoughts, I'd appreciate hearing them. One distinct advantage to keeping 98 for a molasses mind like me is that wouldn't have to learn, and likely screw up, the new OS.