Got mine today as well. Holding next to the exact same (unused) ABS keys from SP, they are virtually indistinguishable. I feel slightly more texture than the ABS. They make slightly different sounds when you hit them with something. But otherwise, there's virtually no way I'd be able to tell the difference.
This isn't bad news of course... they're the same as what we've been buying, but (assumedly) much more durable texture. They're still the too-thin SP molds, which won't change unless they invest a lot of moola.
Regardless, AWESOME of SP to try these out! I probably wouldn't pay much extra for a PBT set vs an ABS set of the same thing, but I suppose some would. (I change keycaps so often that I don't wear out the ABS too fast, plus I kind of like a little shine!)