Ian, my story is similar...I use the same Roland Cubes for 29 years...and to me..they are still the best (retailed for $800 each in 1985).

A few years ago I used them with an Edirol mixer with room control...and there is nothing else I want to use in their place..

I have done high volume outdoor shore gigs...using house Mackies and the band's Yorkville system...and my pair of Cubes...So lound that the Mackies and Yorkville sound systems cut out and were unstable...guess what system kept the party gone?

They don't fail..I have a "new" pair waiting in storage to be used
I won't sell my original pair (memories)..and they are like family

Maybe someday I will use four units...but so far a pair are more than enough..

Yes sound systems make a difference..