Matrix gt1000fx vs yamaha dxr10

There are people who swear by both approaches. The Yamaha is reputed to have transient response more like a conventional cab than most other FRFR.

How have you been listening to the Kemper? Will you be using a lot of different amp sounds live, or a smaller number of amp sounds, and mostly changing effects?

If you like the sound of it at home through studio monitors or similar speakers, you would be happy with it louder with the Yamaha. You also would likely have little tweaking to do:
If you use FRFR for gigs, all the rigs will sound closer to the way they sounded when profiled, in sound clips, youtube videos, in a good set of headphones or studio monitors. From my experience, listening a little off axis (not pointed at your head) pretty much does away with any feel differences at stage volume. Knowing I can pretty much download any sound I like, put it into my Kemper, and use it at a gig without doing anything more than volume leveling it is the biggest advantage to FRFR for me.

What guitar cab would you use with the Matrix? Would it suit all the sounds you will be using? The Kemper has a really effective Output EQ that you can use to make a cabinet more versatile. I used an open back cab at a gig with a fairly neutral speaker in it. It was great for all my gain sounds and for bluesy clean to dirty. Crystal clear sparkly sounds, though, sounded muffled though it. Acoustic sims sounded like a jazz guitar. If I used it all the time, I could likely have made my own EQ preset to add to any Rigs that didn't sound right through it.