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