MRC include a Healthcheck on the car before remapping it. The majority of cars they see are 2.7T's and I can't imagine there is another firm in the UK who have done more development on their maps for that engine.
Revo is a franchise, and whilst they may offer decent generic maps for a wide range of cars, the one local to you may or may not have ever seen a 2.7T in their shop before.
I know where I'd go... (again)