The consoles themselves are OK (except the xbone, it was bad... but it could still have succeeded if MS knew how to handle consoles).
OG xbox: it probably jumped in too late to catch up to the PS2, still, its library is amazing and full of under rated games, or best version of a given game for its generation
360: let's not talk about the RRoD episode, it had a great indie scene, tons of exclusives\timed exclusives, many "better" versions of this generation's games. However the second half of the gen was mis-handled and a preview of what was to come.
xbone: bad launch, a few corrections, then years of distractions and focus on the wrong things (branding, business models, studio purchases... without vision), no stand out titles
series: by that time MS had given up on their platform