I've been trying out the Vega trem on a partscaster for a couple weeks now and I find it to be a mixed bag. On one hand it is pretty incredible how stable it is with almost Floyd Rose levels of pull and dive once you get it balanced, but for me personally I find the balancing part to be a bit of a pain in the ass. I find that any degree of stretch still left in the strings causes annoying instability, as just like with a FR before you've locked down the nut, any turn of a tuning peg sets all the other strings a bit out of whack. I do not find locking tuners to be quite as stabilizing as a locking nut.
I'm impressed with a lot of things about it. It sounds better than I thought it would, given its limited body contact. It holds up to my palm muting and everything without easily being pushed off pitch. For the most part it returns to pitch remarkably well. I think I will probably end up replacing it with a plain old Wilkinson WV6 or something though.