For the STR they are a bit back heavy so I use a decent amount of weights to balance it. About 2/3 of total weight capacity. I suspect the balance point on the trg may be a bit better, but personally I would still get the competition foreend and some internal and external weights. The threads are not what I would call precision machining but I am happy with mine. Folding mechanism is very solid. We have an Impact in an ACC also and I may like some of the details on the ACC a little more, but all in all they are pretty similar.
I have not tried the TRG variant.