Soundstage do their THD+N tests with 10Hz-90kHz BW. This is pretty important to compare apples to apples, not apples to oranges as are the 20kHz BW limited plots in Purifi and Hypex datasheets, limited BW for obvious marketing reasons. Not only this, Rotel has more power, is more beefy to low impedance and will drive Wilsons better, and, as an integrated amp with various inputs is much more versatile.They did do 2 Ohm tests, just not a lot:
I highly doubt it will do better than a Purifi 1ET7040SA based amp. Yes the Rotel has a bit more power, but I doubt that you’ll notice the difference. And if so, get an NC1200, it’s rated for 1R.
On the other hand, the Rotel seems to show decent performance, and it’s a complete package, so that may be appealing depending on the needs.