Comparing the Suhr SL68 with the Alta is somewhat similar (in my opinion) to comparing a 1968 Plexi with a Late 70’s 100W master volume JMP 2203.
The late 70’s 2203 does not ‘punch’ quite like the Plexi, but it has other redeeming qualities the Plexi does not possess.
They’re just a bit different.
I have an original stock ‘67 100W JTM45 Marshall that punches like a Grizzly bear, but I much prefer the Alta for all the 2203 tones I prefer. Plus, the 3 channels, the loop, clipping, vintage / Modern, bright caps, with endless configurations of each, all midi controlled.
All subjective, I guess.
A closer comparison to the Suhr SL68 (in my opinion) would be a Metropoulos Metro-Plex or a Metro DVL-1.