Ordered mine as soon as it popped up on the Apple store and received it on Monday. Base model in rose gold. Amazing. Absolutely amazing. But I just filled out the return form on the Apple store. I cannot adjust to the keyboard. I touch type at roughly 100wpm. My speed was probably half that on the rMB and the number of typos went through the roof. I was willing to give it a few weeks, but I realized I was putting it down after a half hour or so because my fingers hurt. I'm a writer. That's just not going to work for me.
I type 125 WPM and have not noticed any long term decrease in speed or accuracy. It took me less than a few hours to fully adjust, but even right off the bat it wasn't so bad. I actually prefer this keyboard now as opposed to standard ones, it's really not a big deal for some and maybe for others it might be.. depends on each individual's adjustment level.