After three years of hard work, it is time to retire my 8440p and let the family enjoy its availability. For my new workhorse, I have chosen the HP Elitebook EVO 850 that fit my budget and performance requirement.
TL;DR : The Elitebook EVO 850 basic functionalities work fine with Ubuntu 14.04.1
Before hosing the Windows 7 installation, I thought of testing the basic functionalities. So after booting Win7 I checked that most of the thing (sound, light, webcam, etc) did work as expected.
Never underestimate the power of the bug : if there is some hardware issue, then it is better to do a first diagnostic on Windows. The HP tech will love you for that (been there, done that). Otherwise, there will always be a doubt that Ubuntu is the culprit & they will not try to look any further.
After a successful Windows boot, I created a bootable USB stick with the latest Ubuntu release on it to verify that Ubuntu itself runs fine. No need to wipe out Windows and install Ubuntu on it only to find out that the hardware fails miserably. Here is the command I used to create the bootable USB stick, since the USB creator has been buggy for years on Ubuntu :
$ dd if=ubuntu-14.04.1-desktop-amd64.iso of=/dev/sdc bs=4M
One important note : this is a laptop that is factory installed with a secure boot configuration in the BIOS. I did not have to change anything to boot Ubuntu so you should not have to.
Since everything looked good, I went ahead & restarted the laptop & installed Ubuntu Trusty Tahr 14.04..1 on the laptop, using a full disk install with full disk encryption. Installation was flawless and completed in less than five minutes, thanks to the 250Gb SSD drive !