We went to Maroma for our HM a couple weeks ago, and we went to the Valentin two years ago...(Maroma we visited in April, Valentin in May).
We just wanted to say, for everyone looking at comparisons, that you won't be disappointed with either. We stayed 5 nights at both, and had a swim out room. The swim out room at the Valentin we liked better (we liked the pool better, and didn't like that at Maroma we only had one lounger). The pool was much larger, much nicer at the Valentin. The beach was much nicer at Maroma. The staff at both were great, with Maroma maybe being a bit better. The food was also slightly better at Maroma, as well as the amount of restaurants. We never had to wait at Maroma for a seat at dinner - at the Valentin there were times whe we waited up to an hour.
The generally feeling at the Valentin was a bit nicer - there are no other resorts near you, and you feel like the resot is huge (it is way bigger than Maroma). Maroma is kinda packed in with a bunch of other resorts, and you don't get the same isolated feeling that you do at the Valentin. Maroma also lacks the "Grand entrance" feel that te Valentin has.
We used the spa at Maroma - which was FABULOUS! We have no experience with the Valentin spa..but we were very impressed with it at Maroma.
Both have water sports available on the beach for free (kayaks, boats, snorkeling). Those guys work for tips at both resorts, and do a great job.
We did feel a little more "pampered" at Maroma. If we had to go back to one of them, I think we would choose the Valentin. We're more pool people than beach people, and the pool can't be beat at the Valentin. Although, Maroma had fabulous food choices so close to everything. Their buffet by the pool was amazing. The fact you could have food deliverd to you at the pool or beach was amazing. I'm not sure if this is available at the Valentin or not, we never had it though if it was.
Hope that helps someone out there deciding between the two. We felt so safe the whole time on the resort, and nevr had any issues at all.
Happy HM planning to all!