My guess is that either, there is too much dirt below the shift key that needs to be cleaned out, or that the key's stabilizer bar is broken. I don't have a E0610, but I had a KT-1000 (that looks like the E0610) where the stabilizers were made of quite flimsy plastic.
I suggest that you open it up and look at the switch. If it is just dirty, then just clean it up. If it is broken, then see if you could replace the stabilizer with one from a key that you don't use, such as maybe one on the numeric key pad.
That would save you $100. ;-)
As to Cherry MX switches, neither the Black, Brown or Blue resemble the Keytronic's very much. The Black does not have any tactility, and the Blue and Brown have a much lighter touch. All of them will hit plastic against plastic when you bottom out and that could be disconcerting to someone who is not used to it.
I have not tested the Cherry MX Clear, but I suspect that it is more like the Keytronic's feel than any other Cherry MX switch. The Clear, however, is quite rare. It is not available in Filco keyboards, for instance.