Tac Star= Cheap Junk (Having owned one)
Mesa's pretty decent but it's putting extra weight on those bolts with the overall design.
Vang is a shotgun god. The velcro means the only added weight to the receiver is pretty much the ammo. As long as you don't over-tighten the bolts during assembly, either the Mesa or Vang will work fine.
Six shot vs 9: Weight and barrel length. Having cleared rooms with a 20" M16 and a M249, weight and length both matter. In a shotgun, maneuverability is king. 18" barrel and six shots with reloads, top off as you go. Make sure the stock length is down from the factory unless you're 6'2 with long arms. A 13" LOP is probably better for most.
"And Shepherds we shall be. For thee, my Lord for thee. Power hath descended forth from thy hand, that our feet may swiftly carry out thy command. So we shall flow a river forth to thee and teeming with souls shall it ever be. In nomine Patris, et fili, et Spiritus Sancti. Amen."