I'll throw my 2cents worth in here.

Personally, I like the Kinesis keyboard.  It did take about a month of
adjustment.  The first week I hated it - absolutely refused to touch it.
The second I used the tutor some, but still wasn't fond of it.  By the
third week I could almost type a sentence .. The fourth week I liked it.
Now in my great allotment of 10 minutes typing in two hours I couldn't do
without it - I can't type at all on a flat keyboard.

The Kinesis also fits perfectly with a CIRQUE TouchPad2 in the middle of
the keys so there is no more straining to reach for the mouse!

As for the performix trays, I don't like to knock products but IMHO thought
the product wouldn't hold up under daily use.  Again this is just MHO.  I
know many people that love the tray.

And then there's always my voice software, now what would I do without that.
Good luck on your choice and as a recommendation try to buy from a company
that will allow a 60 day no questions asked return.  It takes about that
long to see if it will work and you won't be wasting valuable $$.
Sherri