Has anyone done this? Sounds interesting, but I'm also doing the Antilla on Aruba the day before this, and I'm a little concerned this may be anti-climactic. It's ranked as one of the top 10 sites on Curacao. I'll also snorkel quite a bit from the beach on Curacao.
BTW: Curacao tourism puts out a terrific pamphlet from their tourism office. Anyone going there, I strongly encourage you to order this free brochure.
I've done this and it was actually better than the Antilla. The tug is really quite small but the water is calm and as clear as you've ever seen. There is an abundance of fish of all sorts and maybe even an occasional turtle. I'd do this one again long before I'd do the Antilla again.
The problem with the Antilla is that it's about the only thing to see underwater in Aruba. Eevery snorkeler, diver, and glass bottom boat will be looking for space around this ship. If another cruise ship is in port the same time as your, then every snorkeler, etc. from every ship will be there. Talk about crowded.
Go for it, I think you'll like your stay in Curacao.