Since the RingTrue Reticle Alignment Tool is new, there aren't many people who are familiar with it. I developed it specifically to give shooters an affordable and accurate tool for leveling reticles and installing anti-cant indicators.
Both tools work essentially in the same way. Both are precision devices that allow you to align the turret axis or reticle to the rifle bore. Long range shooters need one or the other to insure that reticle misalignment won't cause large canting errors.
The RingTrue Reticle Alignment Tool is really a 2-in-1 tool that can also be used to level the turret cap. It balances nicely on just about any horizontal flat surface. On my opinion, the EXD Tool is too top-heavy to be used as a general purpose level. With the EXD Tool you really need to use a different level for the cap.
The RingTrue Reticle Alignment Tool is a rugged, durable instrument that will last a lifetime. I tested the durability by repeatedly dropping test samples 3 ft onto a hardwood floor. Under normal use it is unbreakable and won't loose it's alignment.
Then there is the price difference. I designed the RingTrue Reticle Alignment Tool so that it could be manufactured and assembled at low cost. Plus, it is made in the USA. Initially, it is being sold direct to shooters by HighPowerOptics at a low introductory price. When we start to wholesale distribute it later this year the price will go up a bit.