Personally, I love K-27s, K-36s and K-37s, but have never been too bothered about K-28s. It is because I have never been a big fan of the front end, with that air pump standing out.
I base my favourite engines by their whistles. 473 is my favourite K-28 because of her 3-chime whistle, 478 is my second, because of her 5-chime, but I am not a big fan of 476. Mainly because she hasn't been in the limelight as much as the other two, having not run for 19 years prior to last year. And also I liked 476 more with a 5-chime; the Lunkenheimer (I believe) that she has now just doesn't suit her. Maybe when I get used to her she will rise in my charts. Sorry if I was too negative in my previous post.