On PC here so not 100% relevant but.....
I had a Focusrite saffire (one of the original ones) for years and it worked well. On the odd occasions I had issues, the Focusrite support was great.
I then took advantage of a special offer on a Native Instruments USB interface. I was hit with pops, clicks and other horrors and then spent 6 weeks trying to fault find. Whilst I like NI products, I discovered that their support is way below the standard you need and expect..... No answers to support tickets, emails, phone calls. When you finally do get them, the answer is along the lines of 'have you read the FAQ'. And you've already explained in the support ticket that the FAQ had been followed... That was two years ago and I note from their forums that people are still having the same issue!
I now have a Focusrite Saffire Pro 24. No problems.
There are happy NI interface users out there so I can only assume my PC had an issue with the NI Interface. Whether this means I'd have an issue with ANY USB or whether it was poor drivers I can't say as I've gone back to firewire. My PC works well with anything else though.....
My reason for mentioning is because I keep getting told firewire is old hat and will not be supported soon. Indeed, getting hold of a firewire interface is something consigned to eBay and the bargain bin. But if it works, it works :). Look up 'DPC Latency issues' to read tales of woe that only affect USB. I know lots of people have no problems with USB and also some folks have problems with firewire..... It's really a case of finding a format that works on YOUR setup and going with that so but from a vendor who has a good exchange policy.... I was fortunate with my NI interface that the shop swapped it for me to a product that worked!
Good luck 