It sounds like you probably didn't see any premium options, but Harvey is not a terrible choice. Which line is and glass package is that? I don't see "platinum" listed on their website, nor do I see a glass package with .26 u-value.
On the "employee vs subcontractor" issue, that is nothing more than a scare tactic used by some companies, as most have long term relationships with their subs, and know and trust them on a personal level just as they would an employee. I have and do use both, and I often find higher quality individuals prefer to be subs, as they generally get better pay as subs than as employees (= better workmanship). In fact, I previously installed as both an employee and a sub, and once I realized how much better the pay was as a sub, I never went back... and then I started my own retail company. Ultimately, a good installation company will provide excellent quality and stand behind it, regardless of how their installers are classified.
It sounds like you are very confident that you've made a good choice, so congrats. Be sure to post back your thoughts after the install.