I have transitioned from my RC booster that was always on to the KTR that took its place. However, 2 weeks ago I picked up a Fulltone OCD GE and I think that it will be moving the KTR off of my board. It just works for me, I know that some of the other reviews here have not been as positive, but I like an amp that is just starting to break up and the OCD GE is getting me there with my '68 custom deluxe reverb, Victoria 45410 Bassman clone, and my most recent acquisition a Mesa California tweed, better than any other pedal that I have used.
The Emma Reezafratzitz is the one pedal I need on my board because of this. I don't recall too many times that I turned it on and didn't like what I heard. It seems to work with pretty much every amp I've used it with, too. It never leaves my pedalboard.
Happiness pedals... Topanga - just hits the spot for me in terms of Reverb. True Spring - surfs up b*tches! Sovereign - rich, chewy distortion served up right. Belle Epoch - if this one doesn't put you in a happy place, you have no soul.