Tough choice but my vote will go for Hawkwind! why???
because when they are good, they are brillant and can bring you in some ''spheres'' not too many bands are able to..
second reason is Hawkwind is still producing quality music nowadays...they had a few stinkers but still came with great, great CDs in the 80s, 90 s and still now. The return of Davey in the fold with Brock and Bainbridge still guarantees fantastic music ''Take me to the Ladder'', ''Electric teppee'', ''Vortex'' ''Palace Sun'' and others still match the goodies from the 70s.
Kansas on the other hand produced great music as well, but for only a short time---74 to 78-- after that was freefall...
So analyzing their respective carreer, this is 4-5 Kansas great years versus 30 Hawkwind good to great years .
Kansas is now more or less a tribute band of its glorious past...nothing wrong with that.....but Hawkwind is still creating new stuff year after year,.....almost 40 years after their beginning.
So sorry, Yorkie and E-Dub......my vote to the Hawks!. don't beat me up