I like the original Session Horns, and do find it useful more often than not.
I like the demos for the pro version, but can't justify the price. For the same price (upgrade price that is) I can purchase Chris Hein Horns Compact - an equally awesome sounding horn library that is much more flexible.
If it had been $99 for the upgrade I probably would have purchased it, as I am accustomed to the workflow in Session Horns, and the transition might have been easier. As it is I am looking forward to layering CHH and Session Horns!