I think they make the maps to aggressive low down for that 'wow' factor effect of pinning you to your seat and also always wander if they push things to far to ensure they are the top performers. id rather a smoother more progressive delivery which is alot better on the clutch and more tractable especially in the wet.
Also their default answer to a fault is either ' its not the software ' or 'boost leak
That and the fact im rebelling against the big names who over charge compared to equal/comparable products. Don't do revo, miltek or forge( apart from my intake, but that's second hand)
Don't recall reading of any guys on here with celtic tuning