Dylan777 said:
First, ask yourself why did you buy mirrorless camera over DSLR? I highly recommend staying with their native lenses - smaller, lighter, more balance and most important of all faster AF.
Otherwise, there is no true benefits carrying mirrorless with an adaptor and larger EF lenses.
Oh I don't know - there are advantages to mirrorless cameras that have nothing to do with size (disadvantages too, from certain perspectives); besides, the OP may already own a bunch of EF lenses and want to start there.
Anyway, the standard Metabones adapter provides EXIF data, in-camera aperture change (crucial with EF/EF-S lenses, of course), IS support and, for some lenses, AF - but Dylan's right: if you need fast AF, let alone the astonishingly fast AF you get from EF lenses on Canon dslrs (or native lenses on the Sony), you will be very disappointed/frustrated. Speed varies (fastest in my experience is the very lightweight EF-S 10-18mm), but it's never fast enough to use on anything that moves (it seems to be accurate, though, and of course you're spared back/front focus issues). You may find MF preferable, in part because the a6000, like all the better mirrorless bodies, makes MF easy, worlds apart from any dslr (or slr, for that matter). And if you do, you may want to try a few cheap old MF lenses (there are lots of good tips online) and adapters; the focusing rings on those are in a different class from anything I've encountered on a lens made for a dslr, even L lenses.
(I've not tried any of Metabones' speed boosters, partly because I have a ff mirrorless camera, partly because for the price of one of those I could buy a handful of MF lenses.)