Like most, I'm never sure if I have played with enough different speakers in enough different rooms to really know. I love the idea of the RCF NX12SMA, but holy cow that seems a lot of money for a floor monitor. I have a pair of RCF ART 732-A Mk4 that are generally used for FOH PA duty. They are more than OK for full range front of house, and while I wouldn't say they are clinically flat response, I would very cheerfully use one or both of them with the Axe FX III. If you don't need the low profile floor monitor package, and you don't need the speaker to look like a guitar cab, they probably get you most, if not all of the way there for a little over half the cost of the NX12s. Superb mid-cost full range speakers, maybe a smidge brassy, but less than $1000 equivalent here in the UK. And they really do sound good for pretty much anything, including guitar modellers.
More normally I use a fairly big passive FRFR cab (Greenboy Fearless F115) with a Matrix GT1000FX 2U. It is amazing, but complete overkill. I will at some point invest in a smaller FRFR. However, as the OP must be feeling, the wealth of choice and the huge disparities in cost leave me wondering what really might be acceptable bang per buck. Could be the MF.10 from Redsound/G66, but I'll feel a little sick if they don't sound as good as the RCF 732. I guess it's at least a smaller package where I won't need to roll off as much bottom end. Decisions, decisions!
Liam