OK, let's continue this discussion......about 4 years ago I got my F4s from KEH for I believe around 400 bucks, I again think it was EX. I looked at the F5's at the time and they were much, much more money and you couldn't touch an F6 for under a couple thousand as I recall.
Is now the time to seriously be looking for that "nice" F5? I absolutely positively enjoy every moment I spend with my F4s.....time to start searching KEH again?
I'd go even further. Recently, I've had the good luck to find a F6 NIB on Amazon for 1200 Euros. Handily stood in for the used one I stupidly sold.