The only reason I didn't give this attraction five stars is because I think it is overpriced for the amount of time you'll probably spend here. Everything is well done and not tacky at all. The facility is well kept, the elevator looks fairly new and the pathways are well laid out.
We were there in early May and there were hundreds of sea lions in the cave. The cave itself and the tunnels to get there are interesting even without the animals present, but I wouldn't pay full price in that case. They told us when buying tickets that there were sea lions in the cave, but I'm not sure they would volunteer the information if there weren't, so be sure to ask before you pay.
The viewing area is small, but we were there in the off season and it wasn't crowded at all. I wouldn't want to be in there with a crowd though. It smells terrible, worse than you can imagine, so if that bothers you skip it.
We thought it was worth the time and effort to stop and didn't feel ripped off by the price, but I do think it is somewhat over priced. The gift shop was nice and the employees were friendly. Overall I'd recommend this if you are passing by, but don't go out of your way to see it. As others have mentioned, you can see the same animals for free all along the coast.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.