Only about half of the clubs use Motorsportreg, and the BMW chapter does not. Mark's events are good and very long, but fast and not too technical. Depends on the type of event you like. They get going really fast, and have minimal workers.. so you will be doing a lot of hoofing on a cone hit.. while working.
If you want to be with 1ers (there are between 5-10 1's at our events), then the BMW events are your best choice, after that, the next most 1ers would be the Renegade Miata events (Rob & Cheryl do a very nice job).