My suggestion: See if you can find someone who has played through the entirety of GoW I and still has the save game on their memory card. That way you can watch all the cutscenes / story stuff without having to play through the game (obviously the gameply itself doesn't grab you or the first hour would have had you hooked). Your only chance at actually getting in to the game is to get hooked on the story, and get through the gameplay in order to get on to the next cutscene / story plot point. If you get interested in the story elements in GoW I then you might be willing to play through GoW II and be prepared for III.
Otherwise give the whole thing a miss.
My experience intially was meh, onlyu having played 20 minutes I packed it in. I had no interest in a button masher. But then a couple of years later I played and got into the story of the game (with some walkthrough help from my brother who had played I & II so sat through it while I played), and I also found the gameplay had more subtlety to it that I first thought after giving it some time.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix
