This delivers a LOT more low bass than the 4x10 does. It seems to have a lot more depth as well and for some reason I want to say it sounds really rich. Kind of difficult for me to describe it exactly but I noticed it as soon as I plugged it into the Coliseum. Me likey!
I grew up on 15" speaker cabs because I like the way they hit the back of the room. There are alot of great sounding cabs out there running 10" speakers but it tends to take a lot of them to really fill a room with deep , rich lows , and still they don't have the throw to hit the back of the room with as much authority. The older 12" speakers weren't bad , but still I would choose the 15s. These days it's a different story, there are a whole lot of new 12" speakers that give you deep , rich lows like a 15" but they keep it tighter and don't burp and fart like a 15" . And , the biggy for me is they can hit the back of the room like a 15".
I still have several older single and double 15" cabs but my new favorites are running 12"s
Rick