It's good for a laptop. In comparison to same-tier desktop components, it underperforms. I'd recommend not overclocking a laptop, since while overclocking itself does little harm to the CPU, increased temperatures do considerably shorten the lifespan of any computer component. In the case of CPUs, this is most notable above around 80 degrees Celsius, but for other components (such as hard drives, especially) it can be much lower. In a laptop, no part of it is particularly well cooled, so even if the CPU can tolerate the increased temperatures, there's no guarantee that you aren't killing some less tolerant component of your computer instead.
If you absolutely, absolutely NEED more performance out of your laptop and don't have a desktop to provide that performance instead, go for it. But, otherwise, it's probably better for the computer and your lap (and your laptop's battery life) if you don't.