All of the NIB keyboards I have had with Alps have been pretty nice (Northgate and Dells). As far as feel between white and black versions, I can't really tell much difference other than one clicks and the other doesn't. Now that I go back and check, the switches in the ABS feel more clunky than those in the Dell and Northgate. The older (real) Alps feel much smoother, IMO, than the switches in the ABS. From opinion on the forums, the XM switches in the Filco Zeros weren't too impressive, either. The new Filco Zero with the Fukka switches supposedly feel better (they are made in the old Alps factory, and I assume they use the same tooling and machinery Alps used to make its switches).
In any case, when I use a Alps 'board next to a Cherry 'board (keep in mind, I use browns), the feeling is night and day. To me, the Cherrys are much smoother and "butterier" than the Alps.