I use a Dell XPS 17" system, runs smooth as. A friend uses a Precision laptop, cant remember the name but its basically an XPS with a qaudro card in.

The thing is with laptops your paying a premium as the technology has to be that bit more efficient when it comes to cooling and size, and therefore performance, but there not too far behind and you get the portability of it as well.

Make sure you get one with a decent GFX card in and at least 2 gig of RAM, then it should hold up to the task no probs.

Have a look to see if people have any problems with the GFX cards prior to getting it, just in case theres some incompatability issues.

Not too sure what your friend means with performance wise, if he means the memory as in the RAM isnt as fast then hes right, pretty much goes back to the point above about size though I bet unless your doing really demanding tasks you wont notice the difference (I dont).

After having a laptop I'd be hard pressed to go back to a desktop in all honisty.