We dove Cabo in the end of May. I liked it pretty well. There were sea lions, lots of different fishes, a few types of eel, and more that I can't recall right now. We did the North Wall, South Wall, Land's End, Neptunes Finger. There are "sandfalls" at deeper (120' -ish) depths that I really would like to go back and see.
None of the boat rides were longer than 5-10 minutes, and the boats we went out on (through Cabo Acuadeportes, on the beach at Hacienda Beach Resort) were all six-pack types.
The water was nice, but I needed an extra 5mm jacket over the top of my full length 3mm (May-June 75-80 deg.). My hubby went with the rental 5mm and was comfortable. I understand the water gets much warmer at the end of the summer season.
The dive masters told us to come back in October. That it is best then.
I would go again easily. The town is fun, and the diving doesn't suck, and it's not as pricey as say Coz, or other Caribbean sites.
I hope this helps you.