I use a Mooer Trellicopter which is nice for the size. I love having the 3 controls on the outside - Bias gets it from sine to squarewave. It only eats something like 3mA and it's super portable, analog, etc.
There is a slight volume JUMP when engaged though. I guess this is to compensate for the perceived volume drop that happens when half of your signal wave is being faded out through the effect... but unfortunately I find that the Mooer also adds a buffer-style sparkle to the signal aswell when engaged - sometimes I like it, sometimes I don't. I'd prefer it to be more neutral/true to the dry signal.
One day I plan to put it next to a Lovepedal Babyface and see which one wins. But for now i'm happy with it : )
I really love my malekko omicron them. I tried the lovepedal babyface and something just wasn't there for me. It wasn't a bad pedal, but something just didn't feel right. After thought I got my malekko and haven't looked back, although I would like to try a trellicopter and compare.