I've been using this pedal with my keyboard & synths for a while now. I've connected it as a send to my Yamaha MT3X tape recorder, and it works great for this purpose.
First, the delays:
You get a pretty good selection of delays. If you're looking for any specific one, you might find the quality/controls of each delay type somewhat lacking, but that's not this pedal's forte. Each type sounds good and they work pretty well with the instruments/patches I used!
The downside is, as mentioned, the lack of control on each. You get the standard feedback, delay time and level, and that's your lot. If that's enough for you, perfect!
Second, the looper:
There's no way of syncing this thing to anything. You can hope that you get the loop perfectly right with whatever you're playing, but it's definitely a bit more experimental/finicky in that regard.
That being said, I feel like this is the best part of the pedal. The fact that the looper does work WITH any delay (needs some hand-fiddling, but eh) makes this a pretty amazing pedal. It's the main reason I use it with my keyboard: layer a bunch of instruments, and boom!