Optics covered in this post: Holosun HS503G-ACSS Eotech EXPS3-4 To use a red dot with BDC, I highly recommend that you use a magnifier, otherwise it would be hard to distinguish each dot in the BDC reticle. I use a Vortex Micro 3X and with it, the reticle becomes usable under many conditions. Comparison 1. What you got Both sights are well built and comes with a lower 1/3 mount already attached. The Eotech actually has a mount built into the sight so you can't change it but it's a quick detach mount and it is very streamlined. The Holosun has a non quick detach mount attached to the sight but in the box you can also find a low profile mount that you can swap to. The Holosun also comes with bikini lens cover, mounting hardware, and a tube of threadlocker. There's not much else other than the sight itself coming out of the Eotech. The Eotech box does look nicer than the Holosun. Winner: Holosun 2. Build quality Both sights are well built. Both uses aluminum as the main material that made out the housing. However, the Eotech is build more like a tank as the sight uses 2 layered housing design to protect the inner core which contains the lens. Speaking of the lens, both sight have great clarity when looking through, the Holosun has a very slight bluish tint and this is only noticeable when looking at the two sights side by side as the Eotech has no perceivable tint or hue to the lens. Both sights has control buttons built into the housing. The buttons on the Holosun has a very short travel and is covered by a rubber material which helps with water proofing. The Eotech buttons are beefier and requires more strength and travel to actuate than those on Holosun. Winner: Eotech 3. Function This is where you see the main difference between the two approaches of making a rifle optic. The Eotech, built for mostly military and LE, focus on keep it simple stupid. The sight has basically 3 modes: On, Off, and Night Vision. It is designed this way so it is fool proof, on the battlefield the user don't have to fiddle with settings and functions, just turn it on and you are good to go. On the other hand, the Holosun is intended for civilian market, in addition to On and Off, it also offers Night Vision, motion sensing On/Off, and ability to select different reticles. The sight also remembers the brightness setting you left if on it when you last turned it off, an ability that Eotech doesn't have. Winner: Holosun 4. Reticle Use this link to see pictures: https://imgur.com/a/Ef4NLnB Both sights offer a central 4 position BDC with 68 MOA outer ring. In fact, I'm pretty sure Eotech is the inspiration for Holosun in this case. Keep in mind that the photo does not reflect what your eye actually see thanks to spotty camera focus settings, the actual reticle looks sharper to the eye. Also all photos were captured with 3X magnification. One major difference between the Holosun and Eotech reticle is the center "dot" Eotech is know for the clear, crisp 1 MOA dot which looks like the smallest particle that your eyes can pick up. The Holosun uses a chevron tip for the same job, in theory, a tip is even finer than 1 MOA but that's up your eyes to determine. Personally, I'm a big fan of the chevron. Following the "center dot" there are BDC dots for 400/500/600 yards. Here you can see that the Eotech continues with the 1 MOA dots and Holosun uses 2 MOA dots. If you see a fifth dot for the Eotech in my photo, it was not there, I don't know how my phone picked it up but just trust me, the Eotech offers 4 clear and crispy dots. Here you can see that when align the two reticles' "center dot" on top of each other, the BDC is different, with Holosun offers a tighter BDC from 0-600 yards. This is likely due to the reticles were designed for different ammo and zeroing distance, I believe Eotech is intended for 62gr M855 or M855A1 on a 16 inch barrel M4A1 that is zeroed at 50 yards, while Holosun should be zeroed at 100 yards with a 55gr M193 or similar ammo. Eotech reticle has one good feature on top of Holosun's, the 6 o'clock hashmark on the ring can be used for 7 yards engagement. Winner: Eotech (this is very subjective so it is just my own opinion) 5. Battery life No doubt about it, the Holosun with its 50,000 hours battery life beats Eotech's 600 hours square and fair. Holosun even offer auto shut off and shake to wake features meaning you don't have to worry about turning on and off the sight at all. However, if you plan it right and be prepared, you will be fine with the Eotech as well. Eotech's auto shut off is not determined by motion but rather which button you pressed to turn it on. Each time you turn on the sight, it will stay on for 4 or 8 hours unless a button is pressed to refresh this timer. Winner: Holosun 6. Weight: The Holosun with battery installed, without bikini cover, attached to a lower 1/3 mount weights 4.85 oz The Eotech with battery installed, without any aftermarket attachment, weights 11.1 oz Winner: Holosun 7. Low light usage: Eotech being the military focused product, offers better night vision capability, it uses infrared light which can be picked up by your NVG to light up the reticle. Holosun just simply dim down the brightness to a level that will not blow up your NVG. Another good tactical advantage the Eotech offers is under low light environment, there's no light bleed from the front of the sight. On the Holosun, there will always be a light source point to the front of the sight as it is a reflex sight. The clearer glass on the Eotech also means this is the more ideal sight out of the two you should choose for night vision usage. Winner: Eotech 8. Price: Holosun is roughtly 1/3 the cost of the Eotech. If you are a civilian who likes to go to ranges, then I would recommend giving Holosun a try. Eotech is indeed a well made, combat proven optic that is more fitting for operators in the field. At that point the user doesn't pay for its price but the tax payers' money does. However, if money is no concern of you then by all means, get them both and try them both out. They are both very good sights for the money Winner: YOU, after reading this review And don't forget to use BDC red dots with a magnifier. or your eyes will get tired really quickly.