Heads up for the Ditto as well, although I have the slightly bigger X2 model with two tap buttons.
Think about the features you want, and the ones you don't want. Some differences between loop stations:
- battery powered, or plugged into a power supply?
- dedicated tap buttons for starting, ending and erasing a loop, or is a single tap button enough (holding it down = deleting)?
- using layers: some loopers allow you to suspend the latest layers (for a bridge, f.e.) while keep the first more rhythmic loops, and then bring it all back - some don't.
- true bypass (better sound, especially when not using the looping) or not.
- SD card, USB and/or internal memory: pre-recording backing tracks or sound effects, which technically isn't looping, but a lot of loop stations do it.
- effects or not: some have extra buttons for adding reverb, echo, delay, distortion, playing the loop track backwards, slowing it down or speeding it up.
For starters, the simpeler is the better, because it does require some training to get the timing right. Two tap buttons can help. Battery power isn't that required unless you busk. I'd keep effects and memory off the list at first, and go for a pure tone and simple ease of use, unless you want an all-in-one package for travelling around.