My setup is nearly identical to the above: MVP Varmint 5.56, Nikon Buckmaster 4.5-14 SF BDC. It is VERY accurate with handloads. I have shot it in F-Class format club matches out to 500 yards with good results (relative to my skill level), drawing curiosity and favorable comments from experienced shooters using custom rifles. Mossberg cuts the 5.56 chamber with a LOT of freebore, which has allowed me to seat 75 AMAX's far enough out to take full advantage of available case capacity. Fired LC or Winchester cases average 31.1 grains of capacity, with Hornady cases not far behind at 30.9 grains. This puts them very close to capacity numbers I have seen reported for 223 AI chambered rifles. I can launch the AMAX's at 2850 with single digit SD's and maintain very near .25 MOA vertical dispersion out to 500 yards with 8208 XBR. Performance and accuracy is very consistent, despite the 9 twist, which is marginal for the 75 AMAX.
IMO, the MVP's are feature packed rifles that offer excellent value for the dollar. They come from the box with good stocks and triggers. They are also available with threaded barrels for a muzzle brake or suppressor. A good friend of mine has the threaded model and put a Vais muzzle brake on it, allowing him to spot his own hits while PD hunting last fall. Mount a scope, break them in, develop some good handloads for them, and GO! Nothing else is needed until the barrel is shot out. The real downside is the lack of aftermarket pre-fit barrels, which negates some of the advantage of the barrel nut system on the MVP.
In theory, these rifles should also be easily adaptable to a number of popular cartridges, but support from Mossberg and the aftermarket just isn't there. I hope that changes, as these rifles have a lot of untapped potential. A 7 twist pre-fit barrel would allow me to stretch the range to 1000 yards. I have also thought the 5.56 MVP's would make a dandy little combo in 6.5 Grendel (or any of the alternative AR cartridges).