Remember which TRex you're talking about. The TRex 450 has been the one to beat in the electric 450 class-- the 600 is a relative newcomer. In the .30-.50 range, the Raptor/Titan is the king of the hill, and the TRex is the newbie.

The TR450 was the value leader in the 450 range, with good prices and a reputation for quality, but their prices are about average these days. I personally don't see that their quality is great enough to warrant buying a TR reflexively without considering alternatives.