Yes, I had encountered the attitude in the UK in which DL wasn't highly regarded. All in all, though, not too much attention is given to them in the U.S., either. Certainly, they aren't put on the same level as the Stones and Led Zeppelin, IMO. I liked the music of the early Stones, but always thought Led Zeppelin was overrated. I was never really a LZ fan. I was a Stones fan briefly, then got disillusioned. I've always been a casual Def Leppard fan, though, and at least bought a few of their albums.
I might add that to an extent Mick Jagger, Joe Elliott, and Robert Plant all have problematic voices. But when all three were in their prime, I would have actually preferred sounding like Joe Elliott than the other two. But I'm speaking about the past, not the present. Mick Jagger and Robert Plant have withstood the test of time fairly well--at least when it comes to vocals.