I think GRL has a good point about B&M coasters. I have always felt that they are TOO smooth. For most people, this is a good thing, but I think a coaster should feel like it is a little bit out of control. A B&M coaster is a little too precise. Not that they aren’t fun rides, but not the best, IMO.
With that said, my favorite manufacture is probably Arrow. They might not be the leaders today, but they have created a lot of good coasters they have been providing thrills for many, many years.