I use one of these (triple version) every day. It's extremely sturdy and well engineered.
The triple is usually the best deal - Dual is more expensive - but, I just saw the dual stand (for those of us with a mortal fear of hacksaws!) for £35.90!
Usually the pricing for these goes:
- Dual £39.90
- Triple £33.90
- Quad £43.90
Don't be fooled by the low price, someone must be getting them made by the tonne, it's really very well built with thick aluminium everywhere and fine looking welds, broad hinges and a pair of M10 clamp bolts to secure to your desk. monitor plates swivel, tilt and rotate. Strong cable management clips too.
I really like mine, wouldn't risk any other product to clamp screens to a desk.