I use the 4000 and have for the last 8-9 years. They break or otherwise fail to wear or spillage but I've had 4 of them and my hands and wrists don't hurt. If Microsoft ever stops making them I fear for my wrists. Every time I get a new job I bring in my own keyboard or have them get me a 4000 for work and leave mine at home. Best keyboard I've used.

Try the sculpt wireless. No mushy spacebar. I just don't like the esc key - small and different switch style - since I'm a vim user, but its not a blocker. I couldn't stand the 4000.

Yea, I too like the old good "click". Had to spend over $100 for Razer - the loudest keyboard ever!