I used to run with mixed cabs -- 210 + 115 or 410 + 115. Sounded great to me. I never considered matched drivers, because the mixed thing made so much sense: lows from the 15 and punch from the 10s. I rocked this way for many years.
And then I came to TalkBass. The matched-driver advocates -- well, I resisted, but -- they had this science thing on their side, and I think science generally works. So, I really listened to my rig -- with my mixed cabs and with each cab separately. My 410 and 115 actually sounded better alone to me. They were clearer and their individual characteristics came through. The 410 had an in-your-face drive, deep lows, and popped in my chest. The 115 was warm, had clear mids and enveloped me with an airy sound. Together, they were more indistinct and had less character. These were my particulate cabs (GK Neos) and my ears, so YMMV.
Then I spent a day at GC trying 2 410s, 2 115s and 2 112s, as well as the mixed combinations of each. (Let me digress here and express thanks for the patience and service of the GC sales rep who really took an interest in what I was doing and helped greatly moving cabs around to stack them -- not always my GC experience.) My ears told me that the best rig for me was 2 212s; second was the 2 410s; and last was my 410/115 combination. Wish I thought to try this before. I made the purchase and sold my old cabs. (This time, GC earned my patronage.)
Now, I share my story not to bludgeon anyone into the match-cab dogma, as it's been called, but rather to emphasize the importance of trying those mixed cabs and comparing them to matched-driver rigs. Let your ears tell you what to run. But if you haven't compared that mixed-driver set-up to matched drivers, well, do you really know you have the best sound for you?
If you're buying blind without trying, matched cabs will provide predictable results, I have learned from TB, and mixed drivers might work and might not. My lesson was expensive.
And lest anyone take offense, I intend no criticism and no argument. This is merely my experience. YMMV. Rock mixed cabs if you like how they work for you. But I'm a matched-driver guy. Peace, all.