Why are some people saying it is a good mattress and recommending
BUT
they are also saying Dunlop latex is not good/comfortable!!!

As costco latex mattress is all dunlop!

That seems contradictory!

Very confusing.

Different people have different feels. Lots of people love Dunlop mattresses. It's all about finding what works best for you, no one can tell you for sure. Just go lay down on examples of both and see what feels right to you.

Yeah, I hate my Dunlop layer but some people like theirs.
Different strokes for different folks.
Dunlop is - generally - less bouncy, more dense and "dead" feeling, like a rubber mat (as compared with Talalay).
If you like FIRM you will probably like Dunlop.