I think it's got a decent architecture. It's got (from what I can tell) a multi-core multi-tens-of-Gbps-throughput processor for its data plane, where more and more features can be added (I believe the MXO 5 uses two of them, i.e. the architecture can allow for paralleling in some fashion or other. A block diagram showing how acquisitions are processed and where features are run would be great to see!
I don't know Aaronia products (I'm on the lookout for a decent SDR), their interface requirement depends on how much RF bandwidth needs to be captured, and it's very likely they offload any significant processing onto the PC like many SDRs. Perhaps I'm wrong; the system requirement for their software seems quite basic; 2GB RAM, 1.6 GHz quad-core CPU.
I'm currently working with a NVIDIA Jetson board (funnily enough, troubleshooting it with an MXO4), and while the general processing cores on the NVIDIA chip (ARM) are nothing to write home about, the cores which will handle the actual data (CUDA cores) are more interesting, and data is processed without it having to pass through the ARM cores, once that data is in memory. For sure that's a different architecture too, I just bring it up as an example where an architecture can significantly differ from older PCs.
I've looked back at my initial notes/issues lists (with the first release of the software) and UI slowness didn't make my list, everyone has different expectations there, not denying that some scopes may have a smoother UI, and I find some parts of workflow could be improved (for instance, when saving logic captures, it's a hassle saving in several formats, I'd rather save all formats in one go). But I hope they do focus on features as much as possible, get them out the door since they appear to have a decent software release cycle, and UI speed isn't currently so slow to be noticeable when in the zone getting captures/measurements etc. The response to touch always feels extremely snappy to me, but of course the buttons/rotary controls are interfaced differently to that).