You're talking about two of the most inovative and arguable the best coaster manufactures in history. Both share traits while they differ in other traits.
B&M coasters are reliability machines. Their coasters are engineered very well. One thing to note about reliability is the lack of change you see from coaster to coaster. B&M are called cookie cutter coasters, because almost every one of their rides has a loop, a cobra roll, a corkscrew, etc.; but they're all placed differently according to location. To end them off, every B&M is smooth as glass and finding an accident/injury on a B&M is rather difficult to find.
Intamin makes quality coasters (a look at any top 10 list would show this), but they have a share of problems. First off is their reliability. Before I give examples you should note that Intamin coasters are far from the cookie cutter style of B&M. Every ride is custom made for the park (minus the clones, but that has to do with money) and has a lot of updates and new technology packed into each new ride year after year. CP is on the forefront of Intamin's 21st century revolution. Starting out with MF which shaped the way many see just how tall is tall. TTD as we know, was something people didn't think was possible when it was built. Finally, Maverick is bring a few new or at least much more advanced things that we have yet to see on coasters. This allows the rides to become popular among everyone. No one has seen anything like it before. Now back to reliability; new technology brings new problems, end of story. Safety on Intamins can't be explained without debate so I'll leave that out.
I like both, but Intamin has shown so much originality and has made so many changes to how we see a standard roller coaster I have to pick them. They're on the forefront of industry.
EDIT: I accidentally deleted my other post when correct some words. 
-Craig-
2008:Magnum XL-200 | Top Thrill Dragster
2007:Corkscrew | Magnum XL-200 | Maverick