I noticed things become a lot more clean, clear, and articulate. But in reality, nothing changed. I would attribute the difference due simply to the fact the combo amp is now elevated off the ground and pointed a little more directly to ear level. When your amp is pointed directly at you, you will indeed pick up a lot more clarity than if it's sitting at ground level pointed at your legs.
The reason I bought a 210 wasn't because I need more power, although the extra headroom is great, but was because during rehearsals we all have our amps elevated. I didn't like the low end I was losing as a result. So the 210 cab is great because I gain clarity, and the cab reintroduces low end frequencies and the unit is making contact with the floor so people can "feel" the bass again.
So again to reiterate, I now have a bigger, cleaner sound. Which, it sounds like that's what you're after. I'm much happier with how I sound. That said, it doesn't really matter because when I gig it's always FOH out of my pedal board, and my amp is purely for stage volume and a monitor for the drummer and I. If I played a venue without those amenities, then the extra 210 is a no brainer. Again, not because I want my stage volume louder, but I hear and feel things in a way that I'd never had before, and as a result will play better, guaranteed. That's just my two bits.
I should note, they retail for $500. Right? My local shop had one for two years. I finally wanted to try it out so I told the owner, "would you take 350 for it? He said 375. Done! I feel like I walked away with a good deal. I wouldn't have bought it otherwise.