I can only agree with Kelbill. I took my ATP in one of those crash courses in a Piper Aztec and later took the 737 Type at Higher Power. I actually thought the Type (Same profile ATP or no ATP) was easier than the ATP in the Aztec. I think I first felt really comfortable in the Aztec on the checkride itself, but when doing the 737 Type I felt I could easily have done the check after 3 sims instead of the required 5. And my background is all single seat. (I felt the CRM stuff came pretty natural to me)