Crystals rate much lower than Personna Platinum Chrome (called "Reds" by the Americans) for me ... but blade choice is entirely personal.
For me, in my razor, with my face, and my technique, the Crystals were rough and not very sharp. They were usable but not enjoyable, and lasted no more than three or four shaves. I get a full week out of PPC blades.
But if Crystals work for you, then by all means use them!
