I believe that what you essentially wish to know is whether or not there are any major differences between the facsimiles and the modern editions most available in the shops.
Basically both sets are the same: the facsimiles are just published on rougher paper and paler colours in order to give the look and feel of when they were originally published from the 1940s to the 80s.
As far as I know (and Jock123 and others may correct me on this), there are no major differences between the editions, facsimile and modern, the drawing and text being essentially the same.
However, there are exceptions:
the facsimile editions of "America" and "Golden Claws" feature black Americans and Africans who were replaced with white or Arab characters in the modern edition. A good example is the woman with the screaming baby in "America" who is black in the facsimile but white in the modern edition.
Another is "Black Island": the colour facsimile edition is that published in 1943 with the "cars and vehicles" and outfits being of the 1930s: for example, Muller's car is a black Humber Pullman and the trains are steam-powered. The modern edition, published in the 1960s, had Muller owing a red Jaguar MK X and diesel trains.
"Land of Black Gold" is set in the 1930s in the British Mandate of Palestine.
So if you want to just buy those facsimiles which differ in a major way to the modern editions, then I suggest you stick to the ones above.
You should also consider the black-and-white editions which have Tintin as he was published in the 1930s from "Congo" to "Golden Claws". Those are the closest you may get to see how his adventures were published in "Le Petit Vingtième". I do not know if they have been published in English but essentially they are the same general storyline and text of the modern editions so at least you will be able to enjoy the story while comparing how it was drawn in the 1930s and redrawn in the 1940s and 50s.
One exception is "Cigars of the Pharaoh" which includes many scenes in the 1930s edition which were not included in the modern version. I once made an extensive list of these differences in the Wikipedia
entry but it has since been edited out.