I have 6i6 myself which I've (kind of) purchased as an replacement after my long time partnership with AVID interfaces, though I still have Mbox 3 too. Though I primarily work with virtual and DI instruments, I wanted to experiment more with the recording of the acoustic ones too. I don't have very good microphone selection for the time being; just a pair of humble Rode M5 and Audio-Technica ATM600, and with the former, I've never managed to get decent input gain on Mbox 3 without turning the knobs almost to the max. So I've thought Focusrite and its preamps will perform better, but alas there is no great difference here, at least not with these mics. In all other aspects, I must say that Focusrite Scarlett is a quality and reliable device. I haven't experienced any issues with it's drivers nor any compatibility problems with a single piece of software from my arsenal. Also, I'm quite happy with the performance of it's preamps when working with DI sources.