...when I used the thinner to clean it all the bristles came off when I rubbed of a paper towel...
Not a surprise. Tru-Color's solvent base is acetone, which is aggressive and dissolves a lot of things... including CA glues. The thinner likely dissolved the plastic the micro-brush tip is made from (for grins I might try this myself later today).
I've not used the brushable formulation yet, although it occurs to me I may have an unopened bottle or two on the bench for an upcoming project. You may or may not have read my travails with regular Tru-Color, ruining an expensive Shapeways shell trying to brush touch-ups. I love the way this paint sprays and covers, and clean-up is lightning-fast, unlike acrylics. However, given its zero tolerance for errors and the brushability problems, I'm about ready to revisit Scalecoat and see if I can get past the issues I was having spraying it with the new airbrush.