MSRP is $700 so unquestionably this is a great deal, assuming it is the right size for you.
If you aren't sure about the bike I am guessing that you work at REI or similar sports/outdoors retailer that has more than just bikes and your dept is something else. You will get more value out of your discount if you get a more expensive bike, but the Quick 4 is a decent starting bike. You will get better components as you move up.
Maintenance and durability will not change much amongst these models. If you want to ride hard offroad, I would get a mountainbike rather than a Quick.
Don't forget accessories. You will need a helmet, gloves and pump at a minimum. I would highly suggest cycling pants, a patch kit, at least one spare tube, inflator or frame pump, two bottle cages and bottles.