Honestly the 4200 and the Monarch are going to be on average the best glass of the group. The 4200 has a rather limited range of turret adjustment but does have the rain guard. The Monarch will have a bit bigger range of adjustment but doesn't have the rainguard. The Leupold VX-I will be optically close to the prostaff and the VX-II will be close though maybe slightly better than the 3200 and buckmaster line. The VX-III is what compares to the Monarch and 4200 line. Leupold has great customer service which means something as well.
You have to take into account what matters most to you. As a range scope the Monarch will do best. It has the largest zoom of those mentioned, it will have the best(or tie for the best with the 4200) glass, and it will have the most adjustment to let you dial in farther out. For a hunting scope I may go with the 4200 due to the rainguard. Either way those two scopes will be the best to look through of the ones listed. Most of the noticeable differences in the scope will be in low light. If all you are going to do is shoot in the sunshine the VX-II or 3200 may be just fine as well.