Holosun seems to have engineered a way around Trijicon's RMR's patented, hood design that absorbs shocks quite well, by instead using a tougher material to accomplish the same goal. The Holosun 508T is just as compact as the Trijicon RMR, yet it provides a significantly bigger and subjectively much clearer view through the glass than the RMR. The window is recessed from the front limits of the housing and this provides protection from frontal impact.
Sight adjustments are the same as the RMR…top and right side. It takes more force to adjust and the adjustments are significantly more positive than the RMR. It was easy to determine when one click adjustment was made. I doubt these screws will move at all under recoil or anything else. When we installed it and then removed and replaced it, zero was retained. Holosun’s literature quotes 100,000 hours of continuous use of the combined circle/dot reticle on the medium brightness using the battery, and 200,000 hours of just the dot reticle on the medium setting. That is like, 11 years!
This is the highest battery life rating of any powered red dot and surpasses the RMR Type 2's 4-year rating. The HE508T has a revolutionary back up system that will eventually become the norm for powered optics. Their "Solar Fail Safe" solar panel on top.
The optic is designed to run on solar power primarily and will transition to battery use as needed. The optic features "Shake Awake" technology. Initially I rolled my eyes at this, but it has not been any sort of problem nor is there any delay in the dot turning on. The system turns off the reticle after a user-set time of no movement. It turns back on instantly with very slight motion. The user can select between 10 minutes, 1 hour, of more of inactivity. The user can also completely disable this feature and ensure their dot only turns off with manual intervention. Also, when the battery is low the reticle will blink, signaling it is time to change the battery.
The "Multiple Reticle System" includes a 32 MOA circle reticle with 2 MOA center dot, and either the circle or the dot can be disabled as desired. The dot alone is best for hyper accurate shooting, but must confess to no loss in accuracy and an increased speed in picking up the reticle visually when the circle and dot are evident. And in addition, the H508T is rated IPX8 for continuous waterproof immersion greater than 1 meter.
My opinion is that this Holosun optic is a great competitor to the Trijicon RMR, and would not hesitate to use it instead of an RMR on a carry weapon.