Professionals care about tools being quick to use once they have learned them, cost is VERY secondary.
Consider that the ~£6,000 cost of Altium is probably less then a months employment cost for an engineer, if it makes that person 20% more productive, then it pays for itself in less then 6 months....
Lets see:
Rule driven design (This is a biggie, especially if the schematic and layout are being done by different people),
Rooms (draw it once and place multiple copies with component designators and net names updated automatically),
Diff pair routing with automatic length equalisation,
Net length matching generally - Massive once you get to try doing a DDR memory),
Easy to use BOM variants,
3D integration with mechanical CAD (NOT to be sneezed at),
Good ERC options,
Forward and Backward annotation that actually works (And does not have you when you forget to start BOTH packages before making changes).
Now I have not used eagle since V5, so it might now **** less then it did, but I am not looking back.
Regards, Dan.