Here are the details:
Dell Precision 690 = 6000€ TTC :
- Windows XP Pro x64MacPro (default model) + Quadro + 3 years AppleCare = 4500€ TTC
- Bi Xeon 2.66GHz 4MB, FSB 1333MHz
- nVidia Quadro FX4500
- 1GB de RAM (DDR 533 !?)
- HD 250GB
- 3 years warranty.
- and various accessories also shipped wit the MacPro.
The price difference is worth 1500€, for 2 computers powered by the same CPU, using the same chipset (Intel 5000X - complete information here) - and the same GPU. Hardware differences are limited and not necessarily in favour of the Precision: 1 PCI and 2PCI-X supplementary slots but no FireWire 800, nor is there optical audio input and output.
Another interesting point concerning the chipset in the MacPro: it supports hardware RAID as well as PCI-X (but requires optional components, and we currently do not know if they are installed). So Apple could in the future offer new features to its current MacPro line.
Did you say Apple was expensive?