Re: Guitar Amp Modelers
John,
That would be my assessment as well. Creating the sound out of the PA is where the new modelers excel (also recording).
As for the feeling, the interplay between the guitar and amp can only occur through the movement of air (in order to do it properly). A monitor at a reasonable volume level is needed for this IMHO.
@Bob,
I am glad you had the chance to get the feel of some of the best digital guitar amps out there. It is hard for anyone to give up a Fender clean once one has played on one 
The best results I have been able to obtain with my Kemper came from using a Yamaha DSR112 as the speaker. Also while the built in rigs were very good, I found that the profiles commercially made at "The Amp Factory" were a cut above and improved the sound of the device considerably.
I think that there may be a difference in open air, but that it is difficult to tell the difference once you put it through a mic and a PA as JR suggests.
In my IEM's it sounds wonderful 
