It took a long time to find something that could compete with my QLS-1's and they still keep the bar pretty high after having tried several different flagship models including Altec 19, JBL 250, Acoutat Spectra 22, and Magnepan MG-IIIa.
It's largely going to boil down to what reproduction characteristics you prefer, the room and the type of upstream gear you use to feed the speakers. I've had the opportunity to try a wide variety of upstream electronics with all my speakers be it tube or solid state and all of it either restored and updated high end vintage or restored and updated hi-end from the late 80's-early 90's and all amplification has been chosen specifically to optimize the performance and sonic characteristics of the speaker design. My listening space is medium in size (16x20x8), just big enough to accommodate large designs, and is more or less dedicated to critical listening with extensive acoustic treatments and a distributed bass system.
All of the aforementioned models can stand toe to toe with the QLS-1's with each having attributes that make them special but if I had to pick a stand out the Altec 19's would probably get the nod. However, it is worth noting it took me quite a long time to find a combination of upstream electronics that could get the 19's to singing and prior to that I found them to be a not very satisfying listen. I've tried Polk SDA's but they were just the SDA-1c's and to be fair they weren't really a flagship offering. I would have to hear something like the SRS to have a valid opinion of what Polks are really capable of doing. Having said that, I also have Polk Monitor 10's and there is a particular characteristic to upper mid range reproduction from the Polk 6.5" mid-bass MW driver that I don't really care for and I suspect the SRS would have the same characteristic since it uses a **** ton of those drivers. I also have ADS 1290/II's and though they weren't the flagship of the ADS line they are excellent speakers and in a medium sized room can be extremely satisfying on the same level as the big dogs.
I have IRS Betas but they've been a long term restoration project that has stalled out while other audio projects fight for my attention. So, I suspect the IRS Betas have the best shot a moving the bar a bit higher but I also have Altec 604-8Gs that I'm currently building cabinets for and have all the parts to build the excellent and highly regarded Markwart crossover. I also have a pair of Kef LS50's on the way and I'm expecting those combined with my distributed bass system to result in another eye opening experience.
High end Infinity is a great place to spend some time or even settle in for the long haul, but certainly not the last word in loudspeaker performance. The trick is optimization of whatever design you're listening to and if the room is not a good match for the size of the speaker and doesn't have favorable acoustics
ALL bets are off.
http://www.audiokarma.org/forums/showthread.php?t=537607
http://www.audiokarma.org/forums/showthread.php?t=571184
http://www.audiokarma.org/forums/showthread.php?t=650996
http://www.audiokarma.org/forums/showthread.php?p=8480109#post8480109
http://www.audiokarma.org/forums/showthread.php?t=659391
And I just noticed you're in New Smyrna Beach, MiamiBoy. I lived in Port Orange from '90-95 while attending Embry Riddle Aeronautical University. Some great memories made down there!