Thank you for your reply. The specs of each is as follows.
Dell Precision Mobile M4500
Intel® Core™ i7-720QM Quad Core 1.60GHz 6MB
Genuine Windows® 7 Professional, 32-bit
NVIDIA® Quadro FX 1800M Graphics with 1GB dedicated memory
4.0GB, DDR3-1333MHz SDRAM, 2 DIMMS
500GB Hard Drive, 7200 RPM
Intel® Core™ i7 740QM Quad Core Processor, 1.73GHz (2.93GHz Turbo Mode, 6M Cache
Genuine Windows® 7 Home Premium, 64bit
1GB ATI Radeon™ Mobility HD 5850
4GB Dual Channel Memory (2x 2GB DDR3)
500GB SATAII 7,200RPM
I know that the Alienware is way cooler looking and doesnt have any ? overheating problems but the m4500 may have a longer more reliable life because it is a business class laptop and may have better repair/service 3 years from now.
I will use it for gaming and video editing mostly.