It's very sensitive, I brush the Siri activation and "focus URL bar" all the time, at best causing a break in my flow while I get back to where I was and at worst losing data because I'm now typing into the void. I also have to look at it to figure out where things are, which slows me down.

Physical keys were a huge improvement. I'd have loved it if it was programmable keys with little LED displays, but being a flat, easily triggered surface makes it a big loss for me.