Now don't laugh! I have to say my favorite manufacturer is Arrow Dynamics.
Yes there coasters arent very smooth and sometimes they will give you headaches. But that's what I like about them! It gives a thrill to the ride.
And for my second choice I would have to say B&M Inverted coasters. Not there floorless, sit downs, stand ups, or hypers. I just love there inverted coasters especially Raptor and Montu. As for there other coasters, they deliver no thrill.
In early April I went down to Orlando. There I visited IOA and BGT. I do want to say I did not like Dueling Dragons even though they are inverted. Hulk was fun but provided no thrill. And Kumba must be the most overated coaster. This ride was Boring! I found waiting in line to ride it, more exciting.