I personally care nothing for multi music surround, but rather only movie surround. That said, by far, I find that effective diffuse dipolar or similar type surrounds - which are EQd out from the main processor, to match the timber n response of the mains - which envelope the listening area, are of more importance than matching or identical speakers all around. But to each his own. (Surrounds at most movie theaters not same as fronts either!?)
The main fronts n center are BY FAR the most important for anchoring the front soundstage, n carying the content, IMO. The surrounds are mostly for carrying secondary ambiance cues,and should be placed so as to not be localizeable, create a large diffuse side and rear soundstage, and for "fill" (as a priority order, that is -minimumally speaking). Thankfully, it's also most impractical to place larger, even full range, direct firing traditional loud speakers up on rear walls n ceilings, anyway.. Not to mention decor eyesore!
Yes, mostly match main fronts, n work on system set up n integration, proper crossover response n placement, and EQing, I say. let the diehard audiophile music only lovers worry about 5 or more matching speaks! The wife or girlfriend will never love it anyway, otherwise.