I much prefer B & M to Intamin. Don't get me wrong, I think they are both fantastic manufactures, but B&M does have a slight lead over Intamin for me. I feel like on Intamin rides, it almost twists and yanks me too much, to the point of a headache. I also prefer B&M trains too. I love how B&m's are thrilling, but also relaxing at the same time. Intamins are much more intense in my opinion. Which isn't a bad thing, I just prefer the feel (and look) of a B&M.
The reason I decided Intmamin is because, just like stated above, variety.