When I was in theatre on TF-1-07, I saw a multitude of TCCC pouches. Most of the 3VP pers were issued a blackhawk tccc bag in ACU, I didn't think much of it and so picked up a North American Rescue Products bag that served me well throughout the tour. I saw alot of 2RCR folks with the massive issued bag, but I saw many other types as well.
I can't say I'm a fan of the tactical tailor bag on a drop leg, as it just seems A) Too big for an individual TCCC bag B) Poorly organized.
I'd highly recommend if you're deploying as a TCCC provider, make sure you're heading over with a good bag, because you're appreciate a well organized, secure and tough leg bag when you need to use it. The last thing you want is a poorly made mattech bag falling apart on patrol, or having to dig around inside a poorly organized bag.
I'd highly recommend North American Rescue Products or CTOMS based on my (albeit limited) experience.