Wouldn't using a pair of these amplifiers to drive a pair of front and rear speakers be the equilavent of putting a surround receiver on the "all channels stereo" setting? It's can be nice for room filling sound but is certainly not for critical listening. Your additional research gave the OP more information to work with and that's always a benefit.
mceljo -- I have little patience for the mountain of opinion and speculation one finds masquerading as "answers" in these pages -- much less the reasons some feel compelled to always add their "two cents" ;--))
As for the question at hand, I avoid connecting speakers of different electrical characteristics in series (usually) or parallel, to a single amplifier and here's why: an amp "sees" or "looks at" a load made up of the speaker's driver(s), its passive crossover network, and (very important to remember and include) the connecting cables. The speaker designer has anticipated the speaker's performance based on how a typical driving amplifier will drive the load that speaker presents. When different speakers (with different load characteristics) are combined and presented to an amplifier, you are now in uncharted territory in terms of how each speaker will deliver a music signal into the air. You can only be sure that it WON'T be what the designers of those speakers had in mind!
Of course if the user intends to run only one speaker at a time (and not combine them,) it's very convenient to be able to switch from one to the other; and it also allows for the use of different (kinds of) cables for each speaker, if appropriate. For example an electrostat on 'A' and a bookshelf/monitor on 'B'.
Having two sets of binding posts is a feature that makes bi-wiring a lot easier and more economical too; and many amp makers now provide two pairs of binding posts, even without the switching function. You won't have to spend money just for a dedicated bi-wire speaker cable, AND (even more important when bi-wiring) you can try using all those different 'regular' pairs of cables you have laying around to drive the high and low frequency sections of the speaker.
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