We went to the Maldives for the beach, so I'll start with that. Pros: it's quite clean (guesthouse staff rake it at least once per day); the water is just like what you see in pictures; it's just a few steps from the rooms at Bibee; there is some modest snorkeling. Cons: it's the only beachy-beach on the island, so all three guest houses and locals use it; it's quite small (we had no privacy after a group of about thirty young people arrived); there is a strong current and wind on the channel side; it's not the most picturesque place you've ever seen (scrubby trees instead of palms, some broken down equipment scattered about). In short, the beach is pleasant (it's the Maldives!) but not what you'll find at the resorts (unsurprisingly, I guess).
Bibee itself is small, but nice and tidy. There's AC, warm water (a bit salty but not bad), complimentary bottled drinking water. The staff are very accommodating. The food is decent (with several vegetarian options) and relatively inexpensive (5-10USD). One warning: they gave us a large bottle of water for making coffee and we discovered (after using it) that it was rain water and contained some debris and small worm-like things.
The island, Dhiffushi, is a modest place. There is one place for tea and snacks, and few small shops where you can buy snacks, soda, cigarettes, etc. Don't picture a tropical paradise...picture cinder block homes, husks of old boats, piles of trash, and all the other stuff you tend to see in South Asia. Despite all this, it was interesting to see the "real" Maldives, to interact with the people, and to see how people live on a tiny island in the middle of the Indian ocean.
All in all, we had a pleasant four nights at Bibee. But we decided to leave two nights early and went across the lagoon to Meeru Resort (a three minute boat ride). This was actually a nice way to do it. We had some time on an inexpensive island with locals and then had the classic Maldives resort experience. If you're interested in Meeru, check out priceline for discounts.