I enjoyed my Mk1 "Artist" a lot and I owned a Mk1 KTN-100 before that. The Artist is a seriously good amp and truly sounds the best out of the Katanas, though none sound poor at all. I liked the forward-facing knobs of the Artist, slightly larger cabinet (compared to the KTN-100), and the Waza speaker is probably the best speaker you can possibly pair with these amps if you're moving away from the standard "Katana" speaker.
On one hand, the GAFC foot controller will set you back $100+ on its own, so it sounds like the amp is technically costing you less than $300, which is a good deal and you can always move the GAFC to a Mk2 if you ever decide to upgrade.
On the other hand, the Mk2 update did much more to elevate the features of the KTN-100 than it did for the Artist. At this point, I can really only recommend the Mk1 Artist or the Mk2 KTN-100 for being the best values right now. I don't expect prices on the Mk2 Artist to drop for a good while yet.
The Mk2 will probably continue to see some updates for the next year or two, but these are highly refined amps as they are, even the Mk1. Plus, patches for the Mk1 are plentiful (check out Juca Nery's collections) and can be carried over to the Mk2 without issue.