Have built up a bunch of 10/22 thus far - 16 currently,  with at least 8 more to go. 

   Have tried stuff from the low budget simple hammer change to full assembly replacements (Volquartsen & Jard - Kidd pending)     With all that behind me, I can say that in my opinion, for most folks just wanting a simple quick trigger improvement use the Volquartsen hammer and shims.  Don't bother with their trigger plunger spring or hammer spring, both un-neccesary.  Just use the hammer.  
  I've found the PC hammer has given a bit smoother feel but also a very slight heavier feel.  The Volquartsen seems to give a lighter and more crisp feel.  Certainly not a fan overall of Volquartsen's stuff but they have gotten it right on the hammer.  $35 or so, 10 minutes and you're all set. 
