I agree with the two main points made in recent posts - EG - 1) WIM are the best place to get the Omega (and probably anything else) set up.. and 2) We all make mistakes / don't get things perfect / encouter difficulties for all manner of legitimate reasons.
With WIM, what swings it, apart from the complete confidence I have in them, is the fact that they will let you go back, and will listen to your symptoms, believe you, and work with you to improve them.
I can't see likes of 5h1t fit doing anything other than fob people off.
My ONLY negative comment about WIM is that, with the full geo setup, you pay a flat rate. Now this COULD work out very well for someone needing lots of adjustments, however the few times I've been, I've opted for the full Geo, and it's only needed the toe adjusted... so I've essentially paid a full geo price for a quick adjustment.
That said - it's a gamble I knowingly and willingly take... and, I wouldn't take my car anywhere else for tyres and geo. Thankfully, living in Aylesbury much of the time, I can get over to Chesham no worries at all... but even before I did, I'd always make the 180 mile round trip.
Long story short - WIM still get my vote
