The 1060 is a classic. Very well built and sweet sounding.
The "B" series is basically the same as ther "non-B" series, albiet a few less features and sometimes, as in the case of the 1060, slides, in place of some knobs.
The 2275 should be 75wpc.
In regards to build quality, consider them all well built and I'd say of equal quality. I had a 2225 and it was built as well as the 1060, if not quite as beefy.
The 1090 should be, what, 45wpc?
Anyhoo, the 1060 and 1090 seem to be under-rated in power output.