I can't answer that because I have the 115 and a 115 extension cab. Haven't tried the 210. But the 115 combo has plenty of volume. And then when I combined it with the 115 extension cab it was like hearing the voice of God.
I had forgotten how great a 215 rig can sound (and feel!). Rumbles right into your guts!
Didn't really think about how tall they are when stacked together. I sure didn't need them, but couldn't pass them up. I'm thinking I'll feel kinda' foolish playing out with them in this day and age of smaller rigs. But I'm very happy with the sound.