Seabase is the coolest idea ever. They have fairly deep ponds with marine fish and sharks in them that you can dive in. They rent scuba gear and many scuba classes are taught out there by dive shops.
Unfortunately, the coolest idea's sometimes don't pan out as cool as you may wish. The water is very murky and at times you have mere inches or even zero visibility.
If you go out to view it without the intention of diving, at first you feel like, "Wow, I drove all the way out here for this?

" But if you spend some time you may catch a glimpse of some pretty cool fish other than the thousands upon thousands of Mollies that shoal at the shoreline. Some of the fish are VERY large, the ones I saw last time I was there were 3 to 4 feet long. If you find out when they are feeding and go out at that time you are far more likely to see the fish, or at least that is what I am told, I've never been for a feeding.
All in all worth the drive to check it out, but don't expect it to compare to the Living Planet or anything. If you are looking to view beautiful tanks make the trip to Sandy instead, but if you would like to see something a little unusual in the West Desert it is something you don't see every day.