Again  ,    
 
Another  point  I think  worth  mentioning  is bracing.  Bracingis important.. taking a large panel and  breaking it up via  bracing will reduce resonance signifigantly as well.  Just  be sure  when  adding bracing to  fillet/chamfer  all the sharp edges off.   I've seen  some of the  pre-finished cabinets  out there  and they are typically  built using thinner/less dense  material and not  overly  well  braced.  Adding   bracing along with  the  no-rez will be a huge upgrade.
With regards to the DIY route (say heavy floor tile/ 1" OC foam),  I've done it.... a couple times way back when and IMHO, it was a PITA....too much  cutting, too much contact cement, too much  time.  When I built the cabinests for the  OB7's,  i switched to no-rez and have never  looked back. It's worth every penny.... so much easier to work with  and   will save  you  a ton of time.  When you  stick it in place,  be sure to  wipe the   area it is being placed with a tack rag.  Once it's in place,  try to rub  down  with some pressure..... the adhesive is pressure sensitive  so rubbing it down help it get a  good bite/grip..  If it's going over  a  smooth painted surface,  it sticks  basically  immediately  where it's placed so   take your time... it can be   very  hard to re-position.
We use it in all our builds now
jay