Well, he's doing OK, but I would still say Eccleston was the best Doctor since the series returned. He had the perfect mix of quirkiness, seriousness, humour and, well, just everything. He had charm and intellect and I'll admit I fell a little in love with him. He had a great chemistry with both Billie Piper AND John Barrowman and he made it very exciting as well as keeping it down-to-earth.
David Tennant was good too, but he took longer to grow on me (CE had me from the first episode!). He seemed to "mug" a bit too much and was a little more OTT in the role, but still good. He still had the charm and the rapport with the others too.
Matt seems to me to be a little more OTT that even DT was and I hope he tones it down bit as he gets settled into the role. If he does, then I shal enjoy it immensely. If he doesn't, I could well end up getting completely sick of him very quickly.