I was really excited about this upcoming patch (albeit with tempered expectations, considering how the EA release went) and, for me, it has delivered.
Performance is greatly improved (though it will need to get better, still) and I've only really encountered major lag issues when trying to land a 300+ ton vessel on Duna (due to part count). That mission, by the way, should be worth way more science points for what it's asking.
I like the tech tree, it's not perfect but I'm sure it will be rearranged and surely there'll be additional tiers once further updates are released?
What is notably absent though, are robotics, electric motors, and payload bay options for mid to large sized rovers. Are these a planned addition?
Overall, the most important thing this patch brings is a reason to play the game. Particularly for those of us who have played the original KSP for years and the sandbox aspect isn't as much of a draw as exploration, missions and science.
One thing that I would really like to see soon though, is a way to track Science progress. I'm about half way through unlocking T4, missing some from T2 and T3, but I don't know where I should focus my science efforts now as I don't fully recall what I'm missing. Do you think this information is contained in the save file, and perhaps could be extracted with a bit of scripting?