If the configurations are exactly the same,
They never are. at least I have yet to see a notebook with a W series Xeon processor . The rest is not realyl relevant. Even cheap notebooks have enough juice for some good work today, so it mostly becomes a matter of preference. Of course when it's your only work computer, you would buy a quite expensive notebook with a large screen, stong processor and lots of RAM and then it is more expensive than a comparable desktop. Its performance requirements would also greatly impair battery life so it's not exactly a mobile solution....
The major bottleneck I find with laptops is the lack of fast and reliable HDDs, not even talking about RAID. It really depends on how complicated your projects are.