Short version :_____________Pros:- easy to assemble- very robust and sturdy, will hold up very well within guidelines- fairly decent free range of motionCons:- dat price tag $$$$- certain features like cable routing and swivel leave some very minor grievancesLONG version :______________You don't have to read it all, but if you're already looking into buying this, there's a decent chance you are in a similar situation. If I was being nitpicky this would be a 4/5, but seeing as how there's really no other manufacturer that readily provides a solution to my problem it really is just the best I can get, from what I've seen.I upgraded from an LG 34UC89G-B 34" 21:9 to an Alienware AW3423DW 34" 21:9 and wanted to keep both monitors, with the new one on bottom and old on mounted on top. My old 2 arm mount was not going to be able to support this much weight as my other monitor was just a 27" 16:9 and it barely held those together. I didn't want to have to screw anything into my wall and I wasn't 100% sure on my desk space so I wanted free moving arms for orienting the monitors before finalizing where I want them to stay.Once I got this I was able to set my monitors up stacked on top of each other. While the bottom one isn't quite sitting as low as it can go, it's not far off. But the top monitor is just about using the mount's maximum capabilities in terms of being able to space these monitors apart while still leaving a tiny bit of room for adjustment. I have been able to pull my top monitor forward and rotate it portrait for documents and such though I have not done the same with the bottom monitor.______________________________________________________Overall actual use after setup:9/10The monitors themselves are not on the extreme end of heavy but they're not light. They both fall within the specifications of the mount. But where Ergotron excels with the LX is that it will actually support curved monitors up to that weight as well, as the curvature changes the center of balance of the overall monitor and puts more stress when extended out than your typical flat monitor. This is usually where you can see other people having issues with sag when approaching the upper limits of other mounting systems. These have not sagged at all since tightening down the screws and move with a fair bit of range, staying in place afterwards. However I do not extensively move my monitors around often and don't know how well it would hold up if you just kept moving them around constantly, though with the construction quality I'd wager it would be fine.One thing I was told from a friend who has the same mount: if your monitor is really bottom heavy for whatever reason and you decide to use it portrait style, the minor taps and thumps from your desk will cause it to try to rotate back to a horizontal position, skewed about 5-10 degrees. It's very minor and just takes a quick second to readjust but keep in mind that it may happen as 1 side is now far heavier than the other.______________________________________________________Setup process:9/10The setup itself was very easy. I saw other reviews having issues with it and maybe getting some help but if you follow the instructions provided, it is extremely easy, especially compared to setting up other mounts where you have to screw in the whole assembly to the monitor and take the entire piece and clamp it on your desk. You need to clamp down the base and bottom arm portions of the mount, then screw in the upper portions to the monitors BEFORE putting the rest of the mount together. The top arm portion falls right into the bottom and you just tighten the screw afterwards. If you can physically lift your monitor + 8 ounces or so, you will have no issues putting it together. One thing I will note: tightening the actual swivel head on the monitor so that the tension matches the weight of the monitor may be difficult if you are short since it adjusts from the top.WARNING: If your desk is particle board or something, I highly recommend buying reinforcement plates for the clamp. The clamp that the LX comes with is fairly sizeable but if you're going to be putting 50 lbs of pressure on 1 spot on your desk, it's best to not worry about the weight snapping your desk in half. If your desk isn't sturdy material: the arm mount will hold up, your desk will not. You're already splurging on this mount, don't cheap out and break your desk and potentially your monitors by skimping out on a $10 metal plate. If you don't want to go that route and don't care much about aesthetics, you can just use some wood.______________________________________________________Cable management:5/10Cable management looked like a mere afterthought. It's serviceable and hides the cables well enough but it's nothing to write home about. This feature has been better executed in cheaper models.______________________________________________________Range of motion:8/10Range of motion is better than most for sure. While it will still hold them in place, some positions and setups can be limited if you have enormous monitors. If you're using 2 24" monitors you will have zero issues, but the more you approach 40", even on 1 monitor, the options get more and more limited.______________________________________________________Final notes:I wish the pole was longer. That would solve a lot of issues people have had with mobility using large monitors. The arm mounts themselves hold up well, the fitting of large monitors just leaves something to be desired, especially out of something as expensive as this.