Everyone has their own tastes. That said, I do believe it's a masterwork; Moore doesn't owe all his rep to it, but he owes a goodly chunk of it to Watchmen.
There is one thing you probably won't be able to experience that drives some of Watchmen's stature: it's novelty. Like the 1980s NTT and LoSH, there is no overstating what a bombshell Watchmen was when it hit the market. We simply hadn't seen anything like it. Superhero comics of the time were rather formulaic, and typically stayed between some comfortably safe lanes. Watchmen didn't just transcend the lanes, it blew them to bits.