JBL L300 - true myth?


I'd like to ask if some can write his opinion on this speakers,I had a chance to listen and recommened .
I understand they working great with powerfull tube amp...especially with Mcintosh -is that true?
it's look the components are really good Alnico drivers special tweeters,horns...but woofers made of carton?is that a problem with today standards?
Is the old fashion crossover need upgrade ?

Thanks
scubidubi
I didn't know that they were Nelson Pass' favorite speaker.  Interesting because when I worked in the studios, we used to joke that the JBL 4311's were so bad that if you got the mix sounding good on them, it would sound great anywhere.  So maybe that's why Pass makes such good-sounding amps. 
I think he made the statement that they were his favorite back when they were current. He redesigned the crossover for the L-300 some years ago. Got rid of the auto former in the mid-range circuit and changed the tweeter section to a first order instead of a second. Other then that, as he stated, JBL crossovers are hard to improve on in their large monitors, which of corse includes the L-300 which is just a 4333 in a home friendly cabinet.