The effect is not always perfect. There can be a lot of fine-tuning and fiddling to get the image to look right.

I have found that the Vanishing Point tool can be a little slow, especially if you are not on the fastest computer around; seems a little unfair, eh?

When using the Stamp tool, it appears to be blotchy in the way it laid down the color. I find single clicks work best.

Some alignment problems occur if you have to change your brush alignment like I had to do to fill a corner.

The image must be RGB. This may or may not be a big deal for you.

When using the Vanishing Point tool, I found that some of the perspective was off, in spite of the fact that some areas looked bang on.