Nice to see more people giving this game a try.
I've only used my Shield with a full cable connection and I turn off that auto optimisation twaddle that lowers the detail and run everything on max.
It has come on leaps and bounds since they first came out as I had the original model and I found it laggy and to stutter a lot and loads of features like pad rumble didn't work etc.
I have the smaller updated model now but the firmware updates are the greatest improvement.
That said, like most things PC-related, it is still far from perfect and games frequently throw a wobbly.
Now that I have my Xbox One X I don't really use it though. The Xbox is more reliable and consistent especially when it comes to HDR support and I was blown away by Witcher 3 which I thought looked better than it does on my PC due to HDR. Wasn't fussed about 30fps as it was solid and consistent.
So the Shield is really just a fast Kodi box as it is still faster and slicker than my wizzy new HDR TV that cost a bomb.