I use Microsoft Natural Ergonomic Keyboard 4000 for years and do not suffer from RSI.

Another thing that probably helps is that I use table with enough depth, so between my monitors and edge of my table there is enough depth to not only fit my keyboard, but also extra ~15 centimeters space for my arms.

Excellent advice, plus i need to ahve a small hand towel rolled up under my left wrist OTW i get pain.

I switched to that keyboard after I was bothered with RSI. A few years later I started using my laptop a lot more, making it impractical to lug the keyboard everywhere, but I found that the Natural had forced me to improve my posture in general, keeping myarms at 90 degrees from each other with wrists straight.

Now I can type without pain on any keyboard, which is a relief since after using a Thinkpad the mushy key response of the Natural drives me nuts.