I am upgrading my old mac to a Macbook Pro Retina and have been researching audio interfaces. My old setup was a Firepod with (white plastic) mac and that has served me well for many years. My main uses for the rig is to record demos in my studio (solo guitar, duo with vocalist, various other duos, trios and quartets that I am involved in, etc.), record audio for YouTube videos, record some of my gigs for demos and possibly albums to sell and for teaching at schools. I think 4 preamps would be ideal as this should cover live recordings and when recording at home I have a Brick preamp and Avalon U5 for guitar DI to add a couple of extra channels. I have been reading various threads on thunderbolt adaptors, problems with various products and compatibility issues over the past few weeks so thought I would ask for some opinions here. Two possible products I have been looking at are the Focusrite Scarlett 18i8 and the Presonus AudioBox 44VSL. I would very much appreciate any thoughts on these two products and any problems using them with a Macbook Pro Retina, and also of any other audio interfaces that might be an option. Thanks in advance!