I was looking for an efficient way to download the latest MAME romset as I hadn't updated mine since 2015 (i.e. Mame v0.161) and I no longer had access to the sources I once used. Wow, this archive was extremely helpful and I'm enjoying curating my favourite games from the bunch. It took me a long time to get all the CHD files extracted and put in place but boy was it worth it.
Anyway, wanted to give the site operators a huge thank you for preserving the MAME archive here; was totally worth every penny gaining access! :D