The different types of vice blocks all serve different purposes. Vice blocks that lock into the mag well permit both hands to be free when you are assembling a lower. Same with the style of vice block that uses the take down and pivot pin lugs to securely hold an upper. The one I use has provisions for both small and large frame AR's so it was fairly cost effective. They are both handy for general maintenance and cleaning.
I also have a couple of reaction rods, a Midwest Industries URR that has the anti-rotation tab and one from BOTACH without the tab. The only thing I'm wanting is a reaction rod for a .308. If I ever have to take apart my .308 I will buy one, they are that good. The MI rod gets used for torquing barrel nuts and muzzle devices to prevent damaging the index pin. The other is nice because the upper can be easily rotated 360* for stuff like handguard installations or tightening gas block set screws.