@Rick_K,
"The build quality of my MacBook Pro is quite nice. There is little (if any) flex to this notebook, and everything feels pretty robust. I cannot say as much for the majority of HP notebooks I have seen."
HP Elitebooks are very different from consumers HP notebooks and MBP. Elitebooks are MIL-STD-810F certified, something the MBP don't have. Here are more details of what the certification means,
http://www.hp.com/sbso/solutions/pc_expertise/professional_innovations/hp-military-grade-specifications.pdf The MBP are well constructed notebooks, but you feel the difference with you compared the two side to side.
Apple may only officially support 8GB of RAM, but according to OWC, you can indeed put in, and use 16 GB of RAM. The Elitebook surely cannot support 16 GB of RAM.
From the Edge Tech Corp website,
"What is the maximum amount of memory that I can add?
Your HP Compaq EliteBook can support up to 16GB of memory. For optimal performance install the maximum amount of memory in each socket'
http://www.edgetechcorp.com/ram/HP-Compaq/EliteBook/8560p-Memory Although the 8GB is not available right now, it looks like the Elitebook is capable, although not with options from HP.
"You can also get a higher resolution display for the MacBook Pro you have the option to get a 1680-by-1050 glossy or antiglare display, for as little as $100 more."
The 8560p have a maximum of 1600x900 resolution. If you want more, you have to move to the 8560w, a notebook that goes up to 1920x1080, is capable of 32GB of RAM and up to 2GB of video RAM, options not available on the 15" MBP.
http://h10010.www1.hp.com/wwpc/us/en/sm/WF06a/321957-321957-64295-3740645-4307559-5071171.html "There is another issue (at least for me) the standard battery in the HP will only last 2 or 3 hours."
Based on this test, a 8460p lasted 6 hours,
http://www.laptopmag.com/review/laptops/hp-elitebook-8460p.aspx?page=2I suppose that it's a little bit lower on the 8560p because of the screen size, IMO that's a very good battery life. Still, you can move to a 10 cell battery, extended and ultra extended addon batteries.