Time will tell how successful the new diplomas are, but unless you're aiming for Oxford or Cambridge, who still think it's 1863, the existing BTEC National Diplomas are just as good overall as A-Levels for getting into HE (I teach Nat Dips for a living so I speak from experience). There may be some preference depending on the type of HE course in question, but certainly the more vocational courses (IT, Business etc) are more than happy to take students with Nat Dips. Their vocational nature shows that a student is capable of applying his/her learning in real-world situations, rather than just writing essays!