Just not as good. It tends toward "sluggish" shifting if you're "heavy-footed" from a dead stop, for example.
Make sure you read the manual to understand when it will prefer/allow up-/down-shifting. Then you'll have some idea why it does what it does when it does.
I'm in the same boat as you: gotta have an AT so others that don't drive stick can drive it.
I love mine, tho', now that I'm thoroughly acquainted with its quirks. In fact the only time I ever drive it in Auto mode is when I've set the cruise control on a long trip so that it handles hills properly (if in Manual mode, it'll still down-shift to go up a steep hill as necessary but it'll never up-shift at the top of the hill by itself -- you'll have to).
That being said, the next one'll be a stick (unless they're electric by then...)