Single driver speakers. Are they worth considering ?

single driver speakers have very poor higher frequency sound and cant do bass. That is the price you pay for a bit less comb filtering in the mids.

going on three years with my Omega Speakers. single drivers can dazzle, specially with their tone. you'll certainly give up some frequency. quality vs quantity - what makes you happy?

There is coherency in single driver designs that eliminates quite a bit of IMD due to crossovers. A heated up crossover can cause compression, particularly the bass/midrange crossover, and bring a hard presentation if driven. I personally appreciate the immediacy of full range drivers. Dynamics are less affected and again, as a preference, dynamics are on my list of highly desirable characteristics. 
I guess one can tell I like to crank it!

@dentdog-    Intermodulation distortion is caused by drivers, trying to reproduce too many frequencies, at one time.     NOT, "...due to crossovers."       Dynamic/power compression is another subject altogether; again, not caused by the crossover, but- by overloaded drivers.     https://audioxpress.com/article/testing-loudspeakers-which-measurements-matter-part-2#:~:text=Interm....