Review on VIVO Black Quad Monitor Stand Mount – Adjustable, Free Standing, Heavy Duty Glass Base – Holds 4 Screens up to 27 Inches – STAND-V004FG by Troy Drake

Awesome multi-monitor desk mount that doesn't clamp down. Fits two 27" curved monitors side by side. I currently only have 23's above, but I suspect I can make all 4 as 27's. Robust, no risk of tipping. Feedback from people saying it tips over too easily needs to push the monitors too far forward. The pose is not designed for a wide range of motion. Keep your center of gravity near the support leg and you'll be fine.