I recall reading a review of one of the smaller Gallo speakers. What struck me was the philosophy of dispensing with a cross-over network! Given the fact that the BeoLab speakers have electronic cross-overs, this allows them to have a much better frequency and phase response due to equalization in the cross-over network. The cross-over network also protects the tweeters from being overdriven. Also, keep in mind that the BeoLab speakers have their own amplifiers while the Gallos do not. The BeoLab speakers also have the ALTs which evenly distribute the high frequencies.
If you're concerned about the size of the BL 5s for your abode and price is not the concern, I suggest getting BeoLab 3s. There are quite a few available used so you could have a pretty good surround sound system with (4) or (6) + a center speaker. If you'd like more bass than what the BL3s provide, get an active subwoofer to go along with them.
Regarding replacement parts, I know what you mean. I bought my BL5s new, and there was an electronics problem (specifically, the PIN couldn't be re-entered after the units were unplugged due to lightning storm). However, they were under warranty, so the dealer had a technician come to my house to fix them on the spot. He also made sure the PIN system was turned off on both. I think this repair is why the dealer gave me a deal on getting (2) BL3s and a BL 7-4 to have a surround sound system.
I guess I wouldn't be too concerned with something like home speakers. It's not like a car with moving parts that is used in a variety of environments. The speakers I have seem to have rubber (not foam) surrounds so there should be no degradation there. Also B & O seem to have stringent advanced aging testing to make sure things don't break before they are mass-produced (at least regarding speakers!).
D