When I was shopping a year ago, it had to be either an SR or a TRBX.
After lots of practising, I decided the sound wasn't right for me, and discovered that I had developed sufficient strength and flexibility in my left hand to manage thicker necks.
Had I gone for the SR, I could have given it away and lost £300. As it is, making a £300 loss selling the TRBX is taking time and effort.