I have quite a bit of experience racing a '84 B First 42 to Bermuda and skippering her back between 2004-2008. This is a boat that was usually ridden hard and put away (even sailed) wet with 95% of her annual use over 20 years dedicated to Bermuda, the rest occassional club cruises. Basically, a 'no worry' guys boat. Probably like any boat of that vintage, her battery capacity was abysmal but that was my only complaint.
She sails beautifully, is stiff, competitive and safe. The iron keel requires an eye toward maintenance but overall, this boat will take a lot of abuse. Hands down, I'd rank her as my favorite B. If you can find one that shows a lot of TLC over the years, she'll surely last for quite a few more.