I use Shaun because yeh he's a nice guy and gives you the time of day, he's local, many mates use him, and he has a proven record(not that others don't) You will NEVER see any of my cars a Tillbrooks, because i have heard way too many stories about them, and as for all the Keen brothers, ATS i would go too, and the others, well Bill is getting better i hear!
Besides i'd rather my car be tuned safe and at a lower reading than a tuner "tweak" a dyno to make me think he's done a great job so i return to them!
But hey thats my 2c, take it or leave it, i'm not fussed!