Do you like spirited driving? I've owned both auto and manual, and whilst they are pretty comparable in a straight line, in cornering and having the right gear selected to exit is unfortunately where the auto lacks.

The 4EAT (and admittedly the 5EAT would be better in this regard) has a noticeable spot where 1st will be bouncing off the rev limiter but 2nd will be below peak boost (turbo dependent of course), so that at about 60kmh ish you simply may not have the correct gear ratio available (using the manumatic function) . I always noticed this when taking those small curves where you turn left at another road without actually entering the intersection proper. A small issue, admittedly, but the major gripe I had with the 4EAT. This was of course on a 2L WRX, so the torque band on a 2.5L forester will be wider. Plus this is relevant for the turbo FXT, so may not be relevant to an NA Foz. Which Forester model have you been looking at?

Hmm, differences. Clutch repairs on a manual are less than half the price of an auto rebuild. The 4EAT is pretty strong at normal ish power levels, and it's only after about 300NmATW that you may wish to get some supporting mods or take a little care as to how you drive it. But the same generally applies to any transmission.