If I remember rightly, one of the big differences of the FTDI fakes in common ciruclation was that some of the advanced functionality worked and behaved according to the spec. This happens from time to time... the NRF28L01+ radio clones are incompatible overr the air with the original because they followed the datasheet, which was wrong.
If I'm paying for a specific chip, I want all the reliability and QC I expect at that price.