Highly Recommended
Just spent a week there - and can't find anything negative to say. It was all good, and about 50 yards from an amazing beach. Playa Del Carmen is relatively mellow, unlike Cancun, and the beaches are still empty enough so relaxing is still relaxing. Highly recommend getting out of Playa, however, and seeing some Cenotes (underground caves), checking out Mayan ruins, or just hitting some of the less-trafficked beaches down south (Acumel or Oscar). If you're looking for value and adventure, ask where to find the 'collectivo' vans that will shuttle you to nearly anywhere on the Mayan Riviera coast for a couple bucks a head. You travel with others, but they leave every few minutes, and run until 10 at night.
Illusion was a great experience - a newer hotel, with great, helpful staff, a new elevator, an amazing rooftop deck/pool and pefect location.