Yes, I have, but it was several years ago (2005, I think). We needed a hotel room for one night in Rome and got an excellent price from Venere on a 5 star hotel in a decent location.
The hotel was very good quality, but I don't think it lived up to an American 5 star; probably closer to a 4. However, the price was still very good for a 4 star so I had absolutely no reason to complain.
The charge was correct on my credit card, the service was great, there were no complications with my reservation so I had no reason to contact Venere's customer service.
I would use them again. Best of luck!!