I think it really depends on how willing you are to spend the dough. I've bought a few 1/60s in the last couple years, but I tend to shop around alot before I consider buying one. I will say that noone is saying you have to buy all of them. Pick your favorite and go with that. I like the Fast Pack units personally. I still have not bought the Super Valkyrie however, mainly because I cannot find the Millia paint scheme.
I generally do my purchasing at conventions, mostly because I hate E-Bay with a passion that is rarely unrivaled, and 9 times out of 10 the item is from the same guy in HK charging an obscene shipping cost. It generally offsets the lower price point.
Bottom line; decide which one you want and go with that. You don't need all of them.