Ridleys are very good bikes, so no worries on that account. Ultimately, for 2500 bucks, you'll be getting a very good bike no matter what, provided it fits. So get the bike that inspires the most drooll/lust in you - if the Pinarello floats your boat, get that (again the caveat is that it should fit you and the geometry should be suitable for your needs - the LBS should be able to help you with that).