Well, aside from the production Infinite is a good album.
And, Relapse is a very unique experience to me. I'm so glad he made that album and so annoyed he trashed Relapse 2.
It's also interesting that you mentioned these two albums in counterpart as, his aim with both of them was to pretty much max out on rhyming for its sake. The only real difference is the subject-matter, you know... in terms of aim. Obviously the production, flows etc. are diff.
But, he even said around the release of Relapse that he used to just think all that matters is rhyming and fuck everything else and he wanted to go back to that. And... those two albums do go together in my head, and I imagine other people's too.
I don't agree that they're his two best, I think The Marshall Mathers LP and The Eminem Show are. But, I'd maybe rather listen to Relapse repeatedly now than any of his other albums. It's his most addictive and flat-out enjoyable on many levels to me. The phrasing too, it's very unique... much like how his phrasing in the late 90s was very unique...
Like, on a freestyle when he says "that's probably all, cause I ain't awkward at all" - to start a line with "that's probably all"... that's 'probably' all lmao. It's such a funny, weird way to begin a sentence and, he used to phrase things in such a unique way, which automatically made him poetic. And, I feel that he tapped into that again with Relapse, in a different way obviously.
But, he tapped into a character and the phrasing and structure took a new form again. Which was a huge relief after years of monotonous introspection and bitching. Yawn.