noice... the only comment I would make is that it seems a little "flat"... you seem to be going for more of an image based approach, so if the lighting direction in your scene doesn't change over time it wouldn't hurt to just paint in shadows on the texture to give it a little more depth. Also, the wear pattern is too evenly distributed- try adding rain streaks, etc, maybe a few areas where the siding is crumbling just a little...

happy modelling