Pros
My employment with HP lasted only one (1) year, but that year was and has been the best hands-on construction experience I have received to date. HP is willing to give their employees a significant amount of responsibility and freedom to make decisions that can (and often do) have a significant impact on the project. Seems to attract alot of young people (post college to the mid-30's age range) which at times makes for a fun and energetic working environment. Not a bad company to spend a few years in while you are young, have no major personal responsibilities (e.g. spouse, kids, own a home, etc.) and have the energy to maintain the hours and intensity.
Cons
The hours are insanity! 12+ hour workdays and weekend work are standard. There is a frighteningly high number of divorced employees or those with strained marriages (especially amongst the veteran employees or "gold hats" as HP calls an employee with 5+ years of service). Kiss your personal life, hobbies, friends, relationships, or other non-work related interest good bye as they are inferior to the company agenda. Basically, the culture revolves around making work and HP your life - not good for anybody in the long run. *I would like to note that I was on an exceptionally bad project (within the HP Northern California District) with alot of personell issues and mis-management - which is why I threw in the towel after only a year. I have heard some very good things about this company from persons who worked in other districts such as the Mid-Atlantic and Plains.