For Rossa likers, Versa is probably the best option, other than the L92 Ghost spider. I myself bought the spider before Versa came out, but if I had to choose now, I'm not sure which one I'd take...
Spider has better precision, but Versa has better balance, forgiveness and slightly slower meter (not to say that it's too fast for Spider) I tried Max and Nike in the past and they seem OK but worse than these 2, perhaps because of their strange increments.
So IMO Ghost Spider > Versa > Max > Nike.
But in any case my suggestion is to try only 1 putter (or at most 2, but not all) during a free rental weekend, as one needs some time to get used to it and collect meaningful statistics about its performance...
Btw, out of 20 players with the highest yearly earnings, the selection of putters is as follows:
Ghost spider - 6, Max - 4, Nike - 3, Rossa - 3, Versa - 2.
Given that Versa is very new and Rossa the oldest and the most popular at intermediate levels (also probably best value), it pretty must justifies my ranking :) though have to admit that putter is probably the most varying club among the top players...