I've got two tailsuits, one by Onik and one by Ashmore. Onik was my first tailsuit and it served its purpose, briefly. The Onik pants were not high enough (even with lots of arguments with the tailor) and the tail suit looks great but has back line problems when you dance. I think it is because it does not have a small hook that once hooked on the collar keeps back straight. Also, as I am progressing and improving my posture and frame, the Onik tailor didn't offer any tailoring options to do some adjustments--bad service by them and bad investment decision on my part.
I've got a Ashmore tailsuit (measurements were done while I was at Blackpool). It fits beautifully with freedom and room to accommondate muscles movements in the back (which is rather different from Onik suit as it feels tight and restrictive). Plus they will do modifications while I am improving my posture/movements. For me choosing an Ashmore tailsuit is a better investment and while getting some real customer service.