No issues at all, got the Groupon for the mini powerboat for 90 minutes. All the staff we dealt with were very pleasant, polite, and talkative.
We booked in advance, they accepted our international drivers' licenses and allowed us to pay the damage deposit with credit, debit, or cash, which is appreciated as we don't like credit cards. We then filled in a short declaration for our temporary boating licenses and watched a short video, then got our life jackets, went to the boat and off we went.
The boats are OK, not amazing, but not bad. The harbour is limited to 6mph anyway and the islands are a no wake zone. We didn't have any problems with it, it worked fine and they're surprisingly comfy.
All in all, a fun trip out, I'd recommend.