You’re in luck, I currently own both. It’s a win either way, just depends on your needs. I use the RB-112 for practice and small gigs, and right now the Katana 110 is primarily for recording, but I think for practice, jamming with friends, and very small gigs (it has an XLR out) it’s a winner.
As we’ve written, the one-watt option is very good when you don’t want to bother anyone, but even at 9:00 on the master volume, you won’t summon the police with complaints.
I’m an Ampeg guy, but I gotta admit that each time I plug into the Katana I start thinking it’s gonna end up being my default practice amp for home. Give both a listen if ya can!