I have no idea what K-D is up to currently. They were acquired by the Apex Tool Group in 2014.
Originally they shared a specialty market niche with Lisle (and to a degree) Kent-Moore. We carried a few of their specialty tools on a revolving display rack in our stores; door handle clip removers, "triple square" metric bits, and a few other items that weren't available from our "full line" tool vendors. It was all top-notch product targeted to pros.
There was clearly a relationship between KD and Easco at some point:


Other than the shape of the raised panel on the shanks of those combination wrenches, they don't appear to be much different than Craftsman from the same era. Easco was a contract supplier for Craftsman for years.
Other than the shape of the raised panel on the shank on the little 1/4" drive RHFT ratchet below, it doesn't appear to be much different than an equivalent Craftsman model from the same era. The sockets, however, do appear to have gotten more care on fit and finish:
I think the only Allen I own would be some hex keys.
The only other thing I can tell you is that neither Easco or Allen seem to sell very well on Ebay. That combination wrench set has been listed for weeks, and this little 1/4" drive set has been listed now for over a month:
http://www.ebay.com/itm/11PIECE-EAS...:g:rqUAAOSwo4pYOPuO&item=311774506891&vxp=mtr
(> same as my set above, but with a later vintage ratchet and it's missing the #11-1110 5/16" socket.)
Short version: as good (if not better) than Craftsman from the same era.