It depends on whether you want it because its a collectors item or for the music. Kraftwerk are my favourite band and I have all there LPs but I got mint condition original pressings.Id go down this route if its justthe music. Ive not had any complaints about quality at all. I payed between £5 and £10 each for them except Kraftwerk 1 and 2 which are reissues, The originals ive seen go for around £125.
If its because its collectable id snap it up. Its a half decent price. Ive seen them go for way more than £200.
It was mainly for the music, I've got Man Machine, but it's in dreadful condition, I never play it, the fact that these are 180g pressings leads you to assume they'll sound really good, but of course there's no way of knowing how the remastering has been done, if indeed they have been remastered.
As far as Im aware they have been remasterd by Kraftwerk themselves. Their production values are typically very high so id imagine the sound quality will be excellent.
If i was you id go for the original albums though. You'd get all the 9 thats in The Catalogue plus Kraftwerk 1, 2 and Ralph & Florian LPs and the 'Notebook' boxset which has a double live cd and double live dvd for the same money as The Catalogue.