Good advice from Fred as you get a more flexible rifle but I did go the other way because I was 100% sure I wanted a basic LW fighting rifle with fixed A2 FSB and MOE handguards. Depends on what you want. If you change your mind later you'll have to remove the FSB from the V3 or shave it down.
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together.
US Army 1966-69, VFW Life Member, Retired Geek