FWIW, I was doing some RIB shopping this year. I was set on an AL hull but a vendor talked me out of. I use a SeaWise davit system where the RIB is tipped on its side at the stern. He told me that over time, you will get corrosion on the lower part of the hull where water will accumulate between the tube and the AL hull. He said it can take 6-7 years, and can be repaired but due to the labor is a couple boat bucks to do it. He would have made more money selling me an AL RIB than the fiberglass RIB that he did. He also had AL RIB more quickly available.
A week later I was walking the dock and started chatting to a guy that had the very same AL hull RIB I had been looking at, also on SeaWise davits. He loved his RIB. Liked the AL hull. He also said that after about 7 years he had to have it repaired because of corrosion at the hull-tube interface. The repair worked well however he anticipates having to do it again in another 5 years.
FWIW....