The TT 1 is not being made. The 2 is 17”, while the 3 is 19”. The Phoenix is 13, 17, 19, and 21 I believe.
They all are very solid products, have all the things that make ILF risers tunable (LLA, removable grips, ATA holes, plunger hole etc.), have similar weights and come with fantastic customer service.
It’s really just a question of aesthetics/color and “feel” in your hand.
I’ve had two titans and a Phoenix, can’t go wrong with either and I wouldn’t recommend one over the other.
Others to consider are WF-19, Border tempest and a Satori.