I don't recall ever having the problems I've seen other people have with XP and mame or Daphne, or even VP. The only things I can think of are some kinds of office workstations (though the ones I've gotten I've had no issues with), and server machines. Or, in general, anything not powerful enough, and made before, XP. But definitely, the convenience of a UI in set-up, with being able to fairly easily put it away and have it completely out of the way, 98 was and could possibly still be a motivator.
1.4ghz processor is a little lean for XP, without Nlite or TinyXP.