A/D converters are sort of a mixed bag of controversy and subjectiveness. I don't believe anyone would disagree with me in that the mics, mic pre's, source (performer and instrument), and your engineering skills are more important, but I believe the A/D converters are not to be overlooked. I've looked hard at the Lynx product line, and they're great. They are pricey, though. If you're losing contracts because your A/D converters aren't all that, and it's causing your work to suffer, then it's time to invest.
I personally use the latest MOTU 24i/o Core w/PCIe-424, but I've swapped out the Op Amps for something I found to be a bit more musical, and I added an external clock from Black Lion Audio. Between these changes I found the MOTU to quite nice and transients are tracking well. However, don't go this route unless you know what you're doing, and are great at SMT soldering.
My Philosophy: Exponential Cost results in Logarithmic Returns