I've been there "thrice"... You're in for a treat... Great place, great staff. Ask to be on Capt. Kerry's boat if you can. Best whale-shark-finder anywhere... And he'll likely take you to him Mom's house on the Cay for a piece of cake!
Dive operation is top-drawer and the diving is very nice.
If there is any drawback to LB, it's that getting into town is tricky. It requires a punt-ride across a little lagoon and canal, then a 20 minute walk or so along a fairly isolated road into town.
When we have been there, we were pretty much the only people who wandered into town in the evening. I never felt it wasn't safe, but be aware of where you are... And if you can, go in a group. Coming back, you need to arrange a pickup again and you best be on time, or you'll be swimming the canal!
Utila Town is a treasure and you should make sure to get in at least a couple of times. There's some fun bars... Treetanic, Tranguilla.. and a number of nice restaurants.
I was just chatting with a friend who lives and works there just today, and decided I must get back soon... probably with my daughter, who lived there for about 8 months.
Have fun!