you guys are awesome -- I appreciate all the replies -- I'm ordering the nx250 as I post this.
Enjoy your new Clark
My channel www.youtube.com/jstevens2010
A difference in weather shields:
As an option to the Tx it is independently deployable. On the NX it is a cover to the bug net.
Clark includes a second layer on both between you can stuff what you are not using. But, a hidden slit from below is needed if the un- deployed net is to NOT cross the zipper track of the WS.
I use the JRB Mt. Washington 4 UQ on my Clark NX-250 and sleep warm in sub zero weather.