Ive had the B2-Four 3 times now. It's really nice, and the only reason I dont have one now is it started very quickly to be a distraction, always tweaking things etc. Also I got turned on to IR's and these work better for me than the Zoom stuff at home.
Ive still got a MB-60 and B1-Four, but never use them. I did have the B3n years ago. Ive also had the MB-60+ twice, but got rid of them for the same reasons above.
One thing I can say about the newer versions are they do sound better. A bit cleaner and more open than the old ones. The different DI Outs on the B2-Four actually make a difference, and I found I was just that feature for a bit.
Ultimately I find all these boxes seem to have a bit of sparkle missing when I use headphones, but not so much when using an amp.
Im an iOS user but have never bothered with the app, other than a customary look when I got the first B2-Four. Im more a hands on guy, and I feel I need to know what's what with my gear in case im at a gig or can't use the app to make adjustments. I found the B2-Four really simple to use one I figured out what does what and where to find things. I like the extra foot switches on the B2-Four, I think they make for a more versatile pedal, especially live once you get the hang of them.