My last two boats were Catalina 30s. Both had fin keels and standard mains.
Last year when we were looking to replace our Cat. 30 with a larger boat I had planned to again go ahead with another standard main. I too had heard all the cautions about in-mast furling such as slower speed, can't head up
as well and danger of jamming. While checking out a boat I was considering, I had a fortuitous meeting with two Cat. 36 owners both of whom had in-mast furling. Their previous boats had been equipted with standard mainsails. They both loved their trouble free in-mast furling and said they would never go back to the old style. They also claimed that that they perhaps lost a quarter of a knot in performance at most. Their personal experience testimonials certainly got me to reconsider.
As a result, we purchased an 04 Cat. 34 with in-mast furling and I couldn't be happier. It performs great and so much less hassle than the standard main.