When flying into and subsequently out of TXL recently, I was surprised that they loaded from the ground and not the terminal. We were crushed like sardines on the bus transfer from the plane to terminal and vice versa.
However, check in was quick and the terminal itself is small so if everything is running on time you should be fine.
We had a wonderful in flight experience in J/F. Coach looked to be standard and the staff both in flight and on ground at TXL were nice and helpful.