Intenso sells not-so quality discs. Not necessarily crap, but they can be.
CMC, Prodisc, DST are among the brands they have sold.
I remeber some Intenso Prodisc's, out of ten four had huge scratches fresh out of the package...
52x is a very high speed even if the difference to 48x can seem insignificant. Lowering burning speeds may cost you plenty of seconds (but what are you going to use them for anyway? :p) but will almost always increase quality.
And you want your discs to last don't you?