Question about Ergotron LX Monitor Arm with patented CF technology

I would take the 27" version. I have exactly this one and with two 27" monitors there is not much room to manoeuvre. I had to buy an extension. Now it fits.

I have also mounted 2x 27 monitors on it and it works well with the manoeuvring, even without an extension. I would also rather take the monitor arm for 24s. Of course you would be a bit more flexible with the 27er arm, but that depends on the price...