I liked the laid back feel it has.
What I remember most about the movie is the couple and their relationship. I like them because they are witty and strong, and they love each other in a sweet, loyal way that is the total opposite of the saccharine, phony romances I keep seeing in Hollywood films. They are grown-ups and they look like real people and they're charismatic individuals. That's a very needed break from all the bratty, spoiled silly, no-brain teenage movies the movie industry tries (to no avail) to force down my throat.
If it were a samurai movie or something, placed in such an alien and exotic place that your moral code somehow doesn't apply anymore, I wouldn't wonder "Why am I rooting and feeling for a couple or payed assassins?" But although it is placed in our world and our time it's like it's another dimension where it's OK for criminals to be talking to you about morals. They make me want to believe, which just might be the best compliment one can pay to a movie.
I would definitely buy it. And the boss is the giant in Harry Potter.