Are you kidding? NXP has been making ARM microcontrollers for over a decade now. Their peripherals are very mature.
@Jeroen3: I didn't run in any trouble with the LPC11U67 (the one with USB which does have a minor bug in the USB part).
NXP's peripherals are usually reasonable simplistic. Except for the few specialty ones, like sgpio or sct. I did encounter an issue in the SPI of the LPC17 that would always inserts a dead cycle when done writing. But I was attempting to abuse spi for WS2811 led's.
I also played around with one of the first generations LPC43's, those can be considered buggy. But still revolutionary with high clocks and two cores, sgpio, quad spi booting from rom (if it works). They should have fixed most bugs by now.