T206s are so much better than T205s it's not even close. The fact that they were printed over three years in far greater quantities, and remain far more available to this day at higher prices than their ugly little gold leaf floating head younger brothers, shows that vast preference of T206 among seasoned hobbyists and rookie collectors alike.
T205s are uniform in player pose and garish in presentation. And they don't hold up under normal wear -- the chipping and the creasing is accentuated by whitened corners and borders.
And the floating headshots make the players look bloated and covered makeup. I'll take the red or green portrait of Cobb in the T206 set any day over his tiny-headed little bloated and pinkened, then surrounded by stale gold and crudely drawn baseball sketches, T205 counterpart.
About the only benefit worth noting in T205 is the biographical information and statistics. Still, there is something classic about T206s cigarette advertisement and it's otherwise uncluttered back. T205s are like someone took all of the T206 portraits and then crammed a lot of mostly unnecessary crap on them, front and back.
Having said all of the above, this signed T205 of Lena Blackburne is still one of my all-time favorites, and so much nicer than his signed T206 counterpart, where the "artist" mailed it in.