I have no experience with the K1 but it was on my shortlist a few months ago when I was looking for my first 3D printer. It came down to the K1 or the Bambu Labs X1C. I went with the X1C.
Both are fast. Quite fast for a consumer-grade machine. The closed-source nature of most of the X1C had me concerned but I got over that pretty quickly. The reported poor customer service and responsiveness of the Creality brand was my biggest concern after I really dug into the research and talking with users of both. A big part of going with the X1C was the fact that I simply wanted something that would just work. I wouldn't have to fiddle with it very much. I love to fiddle with things. But, I didn't want to do that with this.
I'm not trying to convince you of the X1C. Just my own experience in making the decision. As far as speed, you'll never regret speed. And, an enclosure. So many more filaments to use and options with an enclosure.