This restaurant is definitely worth a visit or five. In my three months stay in Dhaka, I was at Platter more than ten times - it's a really nice place. The restaurant itself is nicely designed, beautiful with threes and running water, half inside half outside. The waiters are very kind, and trying to raise to the service level to what is the standard in the Western world.
One of the chefs has been in Italy for 23 years, so he knows what he is doing when it comes to food preparation. Especially shrimps, shellfish and fish are very well-prepared, though my friend claimed they make the best beef in Dhaka (which is rare, according to him). Sometimes, there are blues or jazz night at Platter, which is a very nice experience.
As almost any other restaurant in Dhaka, they are not allowed to serve alcohol in Platter, but they do some great mocktails. Be aware, they are very sweet.
Also, don't miss the chocolate lava-cake - it's perfect!