You're better off with the 22R. The 21R-U is a Japan-only version so they're hard to get and hard to find parts for. You'd probably never feel the extra few hp.
The 21R-U has less torque than the 22R (116 lb-ft vs. 129 lb ft) so it would likely feel less powerful than the 22R. In a pickup, torque is usually more important than horsepower. Torque is what gets the load moving and pulls you up the hills.
I browsed the forums at pirate4x4 and it sounds like the 21R-U is pretty mediocre compared to the 22R. It doesn't have the torque or reliability of the 22R.
If you really want to do a swap, go for a tuned 22R from
http://www.lcengineering.com/ or
http://www.doaracingengines.com/. You could also look for a fuel injected 22R-E or turbocharged 22R-TE.
is the 21R-U better then the 22R?
Linear Mode
