I use 2 Aguilar 1x12s (SL112s) in one of my bands (and sometimes just 1 of the 1x12s for smaller rooms), and I also own 2 Ampeg 2x10s (SVT210AVs) that I usually use for another band I’m in. Both rigs sound great and having both setups gives me a little bit different sound for my 2 bands. IMO, the Aggie 12s have better overall sound quality and clarity, they also go deeper and can get a little bit louder than the Ampegs... although the Ampegs are still (almost) always plenty loud enough for me.
There’s also a certain something about the tone of those sealed Ampeg 2x10s that I really like too. And because they’re sealed, they’ve come in handy many times on particularly boomy stages or rooms. Ported cabs can make an already boomy stage sound that much worse, but can sound awesomely huge and fat on other stages. But if I know I’m playing on a boomy stage from past experience, I’ll take the sealed 2x10s to cut down on the boom regardless of which band I’m playing with. So it’s definitely nice to have both options.
Another thought... I’d take 2 1x12s over a single 2x12 cab any day, and likewise, I’d much rather have 2 2x10s over a single 4x10... if for nothing else, 2 smaller cabs are way easier to carry than one big cab with the same amount of speakers. And, as others have said, 2 smaller cabs are a lot more modular. I’ve stacked my 2 2x10s vertically, side by side, and I’ve even placed a cab on either side of the drums many times, which is nice for the other band members on the other side of the stage to hear more of what I’m doing if we don’t have FOH support (as well as the audience).