Polished beyond belief, no bugs at all, optimal performance, perfect balance, perfect graphics (even for today's standards, just wow), insanely fun gameplay. It's a painful reminder of what a Blizzard game used to be. I enjoyed it very much, and also got sad.
You know the rest of the story with Reforged, but at least it renewed my interest in the RTS as a whole. When Reforged was announced, back at Blizzcon 2018, I was so excited.