I know what you mean about feelings of guilt - I feel like I'm abandoning my beloved K3.
Right now, i use the K3 for being away from home, and the PW for reading at home, until I get a good cover for the PW. I don't like the official cover from Amazon. but once the cover problem gets resolved, the k3 will probably go in the drawer with my Sony 350. Poor K3! At least it won't be lonely there, but still...