For me it would depend what they are going on.There is a little more flexibility in mounting with the Leupolds, which only matters if you need it. If you need it, you tend to need it alot. I really like that my 11 year old can shoot my Leupold mounted rifles at least at lower powers. There is a huge range of eye positioning were the scope is useable.
As for the second question there isn't as much difference as there used to be. The VX111 has a one piece tube, not that there was any problem with the 2 piece. The MC4 coatings have been on the VX11 for a while now (2004?), and the click adjustments were put on the 11s about 10 years ago. A lot of people think that the current VX11 is about what the old Vari-X 111 was. That's not such a bad place to be, for half the money. I still buy the VX111s, reasoning that the difference in price is only a couple tanks of gas or a keg of powder. That stuff is here today and gone tomorrow but your scope will be on your rifle forever.