For what it is worth, most powerlifters on Outlawpowerlifting.com, Goheavy.com, etc...... recommend the Crepinsek model from
www.1500lb.com or
www.Elitefts.com .
I've only seen a few reviews of the Top-Squat, and they were positive, but if is to see heavy use, I'd probably go with a purpose built bar.