just returned from Grand Baie area and couldn't agree that it's not good for holiday. Generally, it depends on the kind of traveller you are. If look for quiet, peaceful place, you should search somewhere else or, at least on outskirts of GB (for example in Ocean Villas or other hotels in this area). However, if you'd like to have everything available close to you, this is the place.
That's true that beaches over there are not the best (to tell the truth none of the beaches we saw on Mauritius is "beautiful" and we saw almost all of them), but it is very good start point for short trips to Mont Choisy, Pereybere and other nice beaches. GB offers also great variety of restaurants, pubs and shops. If you're on self acommodation, it's very important. You'll find there lots of car rentals, diving centers, banks and other services.