Yeah, another vote for Ergotrons, the only real downside I found about them is the cost, and occasionally a trade-off between height and reach. If you want to move your screens around a lot, for example swapping between computer use and a room monitor. Normally you just set them up for one situation and its perfect.
I have used wall mounts instead of desk mounts when the desk was a bit fragile, plus you can get wall mounts to reach quite far out. Generally wall mounts are more annoying if you ever want to move your room about without leaving a trail of bullet holes across everywhere you move, and having to break out the power drill and anchor bolts.
I personally wouldn't risk the glass desk, although it would probably be 99.9% ok. It will be hardened and very durable, but the monitor brackets put an unusual strain and the momevent is akin to grabbing the edge of the desk with pliers and pulling up or down, and any minor flaw in the glass or unusual jolt on the bracket could just snap a chunk off and take your screen with it. Monitors are lighter than they used to be though, so if you do decide to risk it, I would put some wood tiles between clamps and glass to spread the weight out even more than the bracket does normally.
