I wouldn’t go as far as to call it boring, but it is fresh water so there isn’t going to be as much to look at as ocean diving.
Crystal River has the Manatees so it’s more of a snorkel spot. The springs are relaxing and you have beautiful crystal clear water. Although Rainbow River is on the shallow side it is still a fun dive.
The best part of it all is I’ve never seen a dive shop offer a weekend in this area for over $300-$400 with lodging so it is cheap to do.
I highly recommend it especially if you are a new diver seeking to log some dives and work on things such as buoyancy and air.
I have some manatee footage here from back when I was down there twice a week with school children filming their encounters.
http://ericmelton.info/manatee-video-eric-melton.html