- Lower performance, particularly when you take into account the premium you pay for portability. You're simply not going to be able to play BF3 at full tilt, for example.
- Less storage
- The hassle of having to connect it/disconnect it from an external monitor/keyboard/mouse whenever you want to play. (If you're *not* going to move it, why get a laptop?)
- Lack of expandability
- Noise from tiny fans spinning at 8000 RPM
- While the idea of gaming on the go is appealing, I found my laptop got too hot to use when it was being taxed. Even if I set it on a table, it was almost hot enough to burn my hands.
The idea of a gaming laptop isn't a bad one, as long as you don't intend on it being your primary means of gaming. Most everyone I know who uses a laptop to game also has consoles or a gaming PC as their main gaming source, and the laptop is just for light gaming on the go/on the couch.