Boss RC-505 MKII

Works great – the sound quality is impeccable, and the fact that the unit can function as an audio interface while also applying live FX to vocals and synths allows me to cut out some of the extra devices I'd need in my chain otherwise. I've yet to get a full grasp on all of its looping and mixing capabilities, though, because there are just so many features, but thus far, I am astounded by how much I can do on the fly. It immediately puts you in the mood to improvise and experiment.

The build quality could be better, though. The body feels too light and plastic, almost like a toy. One accidental drop, and this expensive piece of gear is likely to end up in... well... pieces.

It definitely delivers when aiming for basic looping sessions. The workflow is very intuitive and offers the fun it promises as soon as it's plugged in.
If you want to control it with a midi foot pedal like the Behringer FCB1010, it's not going to be intuitive at all, but doable if you put in the effort : you'll have to use the rotary knob navigation for configuration. I did not find an intuitive desktop interface to avoid that.
The built-in effects are OK but not great (reverbs, delays...). I'd recommend using your own effect processors with it. It's a great toy rather but not a workstation. You won't get bored with it.