Horn based loudspeakers why the controversy?

"The Palladium series did look like fine products, but they apparently didn’t compete with conventional speakers well."

They did not compete well mainly because of price points.  At $20,000 msrp for the P-39Fs, these were a huge step up for Klipsch that many "loyal" Klipsch fans just could/would not swallow that pill.  At that price Klipsch would be rubbing shoulders with some heavy hitters and they had not "proven" they belonged in that elite group.  Many non Klipsch folks were just not willing to give them a chance, and I get that.

At some of the current used prices out in used speaker land, these Palladiums are becoming a powerhouse performance bargain.

Bill

I'll bet half their problem is their website. Go there and try to find a dealer stocking a pair of Heresy. In my area I get every ABC Warehouse, Best Buy, and a few electronics shops I've never heard of. You can be sure Best Buy and ABC Warehouse aren't stocking heritage gear and their website makes no distinction. I wouldn't know where to hear a good pair of Klipsch without calling shops for 15 minutes. That's a problem. 

I get the impression from the glowing adoration of horns by some here that their significant shortcomings are being ignored

I can speak for myself in that such is certainly not the case. Horns can sound as good or as bad as anything else.

I won't argue with that. You're generally talking big speakers though. 

I just ordered a pair of Klipsch Heresy lll......  a complete 180 for me but i'm looking for a sensitive speaker that is tube friendly.  Currently have a pair of Quicksilver Mid Monos, that I 'll never sell.... but I'd like to try building something like a bottlehead amp.