Good, solid but limited in both acting and directing.
Acting wise he's not really chosen a big range so it's difficult to pin his quality down and in the films that I've seen him in he's delivered in his roles.
Directing wise I think it's a bit easier. He reminds me of an older version of Ron Howard, although that's a bit harsh. I would say that Unforgiven is probably my favourite of his because it has a richness of themes that I find lacking in most of his other work. Take, Mystic River which I enjoyed first time around but the couple of viewings I've seen since I just had lukewarm reactions to. Most of that has to do with the relatively preditability of the film and direction that felt like a good painting-by-numbers feel to it. He's loved by Hollywood which says more about Hollywood than it does of Eastwood's directing ability.