From my experience, OK a few years ago. I found that it all depends on the uppers. If they are still in good condition then fine, but if the leather has started to "sag" then they dont come back the same, plus I found the new soles outlasted the uppers, and ended up buying new boots before the soles wear out.
Probably me, and the way i used the boots.
Ratio of resole : new boot price still remains the same though!