I can't really go back to Mx Blue since I've tryed Topre. They feel really like they're missing something. And I'm not even a great fan of Topre...
Well, actually maybe it's because my only Mx blue board is no that awesomely built (Noppoo choc mini), so it's only logical that I prefer Topres in the great quality Realforce over Mx Blues in the Noppoo.
For Mx Black I guess I'm ok

, even though I don't use them often (not a lot of gaming here). They still feel solid and actually really different than Topre so for me it's not even comparable.
That said, if I was in OP situation I'd keep the Topre (if I have only one board, I want it to be tactile!).
The only switches to which I can always return are BS.