It's about time! There's really no reason not to be operating in Stereo these days. IMHO, I find mono FM to be kind of dull and lifeless in sound. The bumper music in Stereo adds a nice dimension to that sound. Here in Boston, we've got the 100,000 watt WGBH who is talk by day, Jazz at night. In comes the Stereo generator at 8:00 PM. During their news and info block, they switch to mono. None of the bumper music is broadcast in Stereo (which off the bird IS in Stereo). The other station in town (WBUR) only puts their Stereo generator during "Con Salsa" (late Saturday nights) and during selected programs such as "Marsh Chapel" and some NPR music based programming on Sundays.
I always thought WNYC-FM/93.9 was one of the earlier converts to Stereo back in the 70's. Oh, well. Most FM receivers have that God forsaken "Stereo Blend" circuit that only allows you full Stereo separation within the 60 dBu contour (City Grade). Most FM station have a usable coverage area well beyond 60 dBu. Before the days of the blend circuit, I was able to get a totally usable Stereo signal out to the outer fringes of the coverage area. In my neck of the woods, most Boston FM's can reach about 80 miles, almost to Palmer (about 20 miles east of Springfield). Once you get toward the higher elevations on the east side of the Berkshires, the Boston FM's come back in their full Stereo glory for about another 10 miles or so (almost 120 miles away from the transmitter sites).