I am working on a documentary with all footage AMA linked.. we have all sort of different formats and frame rates and on some timelines avid works great but on others its very slow and sluggish.. i mean it takes 8-9 seconds to register a key stroke.. I have roughly 22TB footage running trough AVID.. h264 is the worst, but most of it is converted to ProRes.. Also much of the footage is RED Raw..
Experience shows...never actually edit when only linked via AMA. AMA is just what it says..."Avid Media ACCESS." Once accessed, the media really should be transcoded to Avid media...either high quality DNxHD if you have the space, or offline quality, like DNx36, if you need to conserve space, and then relink once you lock the cut.
I can really only recommend AMA link editing if you have very little footage, it's a short project, and your media is professional quality, like ProRes, or XDCAM or DVCPRO HD...never MP4 or H.264.