I've gone pretty much exclusively to Holosun for my my new handgun MRDS purchases as well as their larger multi-reticle Red Dot optics for my PCCs. There is not much not to like about Holosun in terms of innovation, performance and rugged durability. Their 507C and even moreso their new Titanium 508T series of MRDS give the RMR real competition for half the price, with a slew of advanced features that the RMR simply cannot match. I've been running 8 RMRs, 5 Deltapoint Pros, 1 Vortex Venom and 1 Razor, 1 Mepro, 2 Aimpoint ACROs, and 6 Holosun 507C or 508Ts (and counting) on my pistols and PCCs, alongside a couple of MROs, a Triicon Reflex, an Aimpoint T1, and several Holosun HS 515CU sights. Suffice it to say that I've had plenty of opportunity to compare the various offerings alongside one another. I am admittedly not running operations with any of my sights these days, however I can certainly still judge them on the basis of build quality, optical quality, features, basic performance, and so forth. There is also a ton of online video content to assist in formulating opinions with destructive testing of most brands and round-count testing that most of us will never approach in our lifetimies!
The recent Holosun 508T with the Green Circle-Dot Reticle is my current personal favourite among the Micro optic offerings. With their Shake-Awake technology, Solar back-up and ability to run without batteries on even artificial ambient room light, there is not much to dislike about the 507C and 508T series pistol/PCC sights. For my PCC/Short-Range Carbines I currently favour the very recent Holosun HS 512, which is essentially the 510 open-emitter design enclosed with a redesigned and improved solar power system. It works great with the Holosun or other brands of Magnifier, as you have discovered with the HS510 series. Exact same idea with the HS512, only with the added convenience of accessible protective lens surfaces for cleaning. And the confidence that comes from knowing that nothing can interfere with the laser emitter and the reflective screen that the reticle is displayed upon. No worries about snow, dirt/dust, debris, etc. I quite like the new 512 with the subdued "Holosun" advertising.
So far my Holosun optics have routinely outperformed my expectations for their price-point. Battery life with the solar-assist models is virtually indefinite. They are rugged and dependable, with the new Titanium housings taking those qualities to a previously unknown height that is easily the match of Trijicon's best. Just check out Aaron Cowan's (Sage Dynamics) destructive testing of the latest Holosun optics on Youtube. Impressive performance is an understatement.