Hi John,
What I know about MBS is from conversations with friends and business partners and it is certainly a good school - though not my first choice for Entrepreneurship. But then, I'm biased...
I did the Cranfield MBA in 2006/2007 and I believe it was one of the best decisions in my life.
When I started the programme, I had already started a my consultancy business in Germany (SAP) and grown to 1.5mn revenue (>2mn now that I'm selling my last stake). But the Cranfield programme (not just the entrepreneurship elective) taught me an awful lot about starting and growing a business and about myself as an entrepreneur. An invaluable armoury, which helped my through the tough times right after I started my second consultancy business in London with 2 fellow students (reaching 3mn revenue now and profitable). We also started another business this year (not a consultancy) which looks promising. The course completely changed my perspective on entrepreneurship from "I start a business to create a job for life for myself with some degrees of freedom and good fun" to "I start businesses as and when opportunities come up and work on them rather than in them as far as possible to grow them to a point where they can be sold or floated profitably. Even more fun as much more diversity and the act of creating sth. valuable new is experienced not just once".
And the course also gave me a lot of the confidence, tools and contacts to see it through.
Well, I'm already pushing the wordcount limit - you'd not be the first person to regret asking me about Cranfield as I just love sharing this great experience. Hope I could help you a bit anyway.
All the best, no matter which way you go!
Sven