TL;DR: if you were to buy a 2nd kemper to back up your main rig, which one would you buy?
I fully converted to kemper a few months ago. I'm loving every second of it and I don't see myself ever going back to traditional amps. The one thing that worries me is a potential backup plan. It's not that I don't trust the kemper, I'm just the kind of person who always likes to have a backup for everything. I know failures are a possibility with any type of gear but if you have a traditional amp/pedals setup, you could either go direct to the sound board with your pedalboard or maybe borrow a backline amp or someone else's amp if there's something available. With a kemper rig being so self contained, I feel like you're a little further up the creek without a paddle if it fails.
SO...all of that is to say: If you guys were to get a second kemper to backup your main kemper rig, which form factor would you go for and why? Also...what's your main kemper rig? The main rig form factor probably has some influence on which form factor you'd go with as a backup.
For me, I have a power rack that's mounted with my in ears, guitar wireless system, and the power conditioner. On one hand, I feel like a non-powered rack would be a good backup that I could mount in the same rack case as my main rig. It would allow for quick and easy switch-over should the main one go down. The drawback being that it would require me to get, at minimum, an 8u case which would be pretty damn bulky/heavy. On the other hand, a kemper stage might be perfect since I could keep it in the carrying bag at the ready. It also might be nice to have a smaller, even more self contained unit to have around at home for recording or for the studio.