The actual pay scales are very similar, but we both know that doesn't mean much. Higher guarantee at Blue, but beyond that there are probably 100 other ways to contort the pay at each. I'm not familiar enough with K4s new contract, but I'm sure if you voluntarily stay out you'll be compensated pretty well. I miss the style of flying that k4 does, and if I didn't have a family life that took priority in my life, I'd happily go back to it. It suited me pretty well, I enjoyed the excitement, and I loved the traveling. A little more job security would be nice, though!
And yeah, I've have an app or two out just in case.