Welcome!!!
Let me be the first Bushmaster and J&T owner to chime in here, if I may.
Today, I took both AR's (and a butt-load of other guns, of course) to the range, but I specifically put my AR's through a bit of a wringer. I wanted to get them a bit hot, fire them as fast as I could, and basically just treat them as rough as I could... for a few minutes. I don't want to ruin them, afterall, but I wanted to put them through a high-temp/high-rate of fire for a bit to see how they would do. The Bushy did as I expected it to do; not a hiccup. The J&T? It did JUST AS WELL! As a matter of fact, there was no difference in how the two acted; they were both spot-on, reliable, feeding properly, and staying on target. I didn't let the barrels smoke, because like I said, I don't want to punish the guns or damage them, but I figured two mags each of rapid fire (pulling the trigger as fast as I could) would at least let me know how the weapons would handle a quick exchange of fire, if neccessary.
Grade? A+
Both are great weapons, both are reliable, but one of them was put together by me which was not only a money-saver, but was FUN FUN FUN!!!
I recommend the J&T for it's reliability, fit, finish, and value. You won't be disappointed.
As an aside, my friends that went to the range with me today said that they want more details from me on J&T kits; one of them is considering the M4 kit.