The bad news is, everything comes from compressed masters. This is common for a lot of rap and hip hop music. Now, that being said, there are definite differences for some which I will point out.
1999 Eminem - The Slim Shady LP
These ones I was close to call the same, but on multiple listens it was apparent that the vinyl was just a tiny bit less harsh than the CD in terms of loudness and bass, definitely not too noticeable, but it is there.
Marshal Matthers LP
This one sounds the exact same as the CD. However, whoever recorded the LP did it at too high of a volume and there are quite a few instances of clipping. It isn't even to change it too significantly, so I am still going with my opinion that it is the same as the CD.
To my ears it's definitely same exact CD masters and limiters, just pressed onto LP.
The difference in this is quite easy to notice. It is not an insane jump in quality but it is a decent amount different and the vinyl is easily better than the CD. It does not take expert equipment to realize the difference in this one. You can hear the guitar so much clearer in "Toy Soldiers" on the vinyl.
In Deja-Vu, the organ and guitar is just so much clearer sounding on the vinyl than on the CD. The CD this is just muffled sounding. I wouldn't say it's an audiophile pressing or anything, but definitely quite a difference from the CD that is very noticeable.
For the above 2 releases it looks like they went the route that some companies do which is, not use limiters on the vinyl pressings. Limiters are commonly used on CDs since they don't have full dynamic range, so they can be easy to hear even on ****ty 99 cent store headphones. What makes limiters even worse is there are used on already compressed masters that don't even come close to full dynamic range. So with the two above LPs I believe you are getting the same compressed master, but without any limiters, and the sound is noticeably better for it.