No go on the 30" monitor, let alone the 3x 27" monitors I have. If you only want the monitors to be straight, without a curve around your keyboard workspace, it will work. If you want any sort of curve, the arms are NOT long enough.
Utilizing 2 of these, as they were on sale for black friday, I was able to dismantle, and utilize the poles, as well as only a single arm for 2 monitors, not using the center monitor mount at all. infact, I removed it, as I want a stream line look.
If you want a better cap without a hole, I found on Thingiverse a cap to be 3dprinted. Works well. https://www.thingiverse.com/thing:4288669/files

Overall, several manufacturers of this same style, with all the parts, pieces interchangeable. Very helpful.

Tried using longer arms, but canabalizing one of them to make a single mount with 3 arms on each side. The metal and plastic components are just not strong enough to hold the weight of a 27" monitor. the fatigue of the metal and plastic just resulted in over an inch of sag of the monitor on the left to the center monitor, even trying to correct with the adjustment screws. It would have been only a matter of time before it would fail.
Inevitably went with using 2 separate mounts to achieve 3x 27" monitors that were curved around my work space.
In the end, very please by doing it this method, as the single mounted monitor overhangs on desk, and allows for it to be swung out towards clients needing to see the screen, and then rotated back to make the triple monitor setup very easily.

Both 27 inch monitors sag about 1.5 inches below the top of the center monitor - both well below the maximum weight at under 12 lbs each. There is hardly any angle in the tilt of the side monitors with all three 27 inch monitors.

Every triple-monitor mount I've seen is normally well north of $100, but at $45 on sale, this is one of the nicest-quality things I've ever purchased for my computer or desk area.

I've never ordered anything but cables from Monoprice before, and I genuinely cannot believe how well organized and packaged it was. The mount was fairly easy to set up, mostly intuitive to put the monitors on, and an absolute breeze to adjust.

Very sturdy and easy to set up. I would give it five stars but the vertical adjustment of the side supports is not well-designed. The adjusting screws are counterintuitive and very difficult to align properly.

Not much more to say. Take care when assembling it and keep in mind that the larger the monitor, the less angle you'll get out of the arms.

So far I like it. Pretty sturdy for it's size. I use 2 29" ultrawides on it. That's all it fits the center mount is mostly covered by them. Wish the center mount was height adjustable for a third smaller screen but the ultrawides should be able to handle the work load.

It works as advertised.

Once set up holds really nicely. Good for situations where you're going to set up the monitor a certain way and leave it there. I wouldn't use this to constantly move things in a situation where you're always shifting a monitor around.

I used this with 3 monitors with identical VESA mounts, but due to the sloppiness of the joints the arms sagged past the full height adjustment of the outside mounts. Additionally, the arms are definitely not long enough to comfortably use for 27" monitors, maybe 15 degrees of turn? Hardly ergonomic!

This works perfectly with my three curved 24-inch monitors. All are perfectly aligned. I believe the reviews posted by those complaining there was an inadequate range of adjustment for the outer panels sagging and being lower than the center panel is due to user error. There is more than an inch of adjustment for the height of the other panels, but the adjustment works in reverse of what one would expect. When I first began fussing with it I was frustrated until I realized I was going in the wrong direction. As soon as I corrected my mistake the problem was solved. There is still more adjustment range than necessary.

The product is made well. It is very sturdy. The only thing I dislike is the clamp mount. I would prefer a heavily weighted base "foot" to allow ease of movement after assembly.. Having it clamped to the desktop is not ideal, but I could not find what I wanted in that design.

You will not find a better triple display stand at this price. I would definitely buy it again and recommend it to others.