Howdy from up north!
I am also shopping for a wood splitter, there seems to be 3 options here,
-Rear Hydraulic remotes from the tractor
-PTO powered
-or Briggs& stratton type engine
Well, I don't know about you, but upkeep on another small engine, is the last thing I want to be doing, and the PTO drive type would include it's own pump, and a constantly moving shaft to work around, just think of all of those moving parts, just waiting to break..and your tractor is still running the whole time, Why not utilize it, so....
IMHO, the best and simplest, and almost break proof way is to use the tractors own hydraulic system and use rear remotes, it is alot simpler, and cheaper....
Hope this helps
Ken