Re: Which one do I get???!!
I have a '02 S2120x, and love it. Lo-Pro w/ piezos. Now if I could replace it for an EdgePro, I'd do it with no regrets. There is minimal difference in feeling but I tend to lean toward the lower profile EdgePro. I think it is indeed an improved design.
If your concern is locking studs, then buy them from Rich for $40. Take the opportunity as well to buy a few extra string retainers just in case one ever breaks, and extra $2 investment, and you're in heaven.
However, the price difference is considerable. If cost is an important factor for your decision, then I'd say, by all means, buy the cheaper w/ LoPro. The tremolo itself would not justify paying $1,000 more.
Last but not least, I also am, as Dee said he is, very sensible about bemishes. Depending on the severity, one or two chips may be well worth the extra difference if you also consider the tremolo factor. But again, it all depends on your financial situation at the moment.