The UK office simply doesn't have the replayability of the US office. There are too many silences that are broken by outbursts that get less funny. And that's why it was only two series long, it would be hard to carry it on in any sort of meaningful series. The US version noticed this and effectively changed it into a sitcom by series 2.
I watched the UK version again recently, and I haven't seen it in ages. It captures perfectly the boredom of working in an office, and a lot of scenes are just boring mundane stuff. Some of the more memorable moments for me were the outlandish parts (Brent dancing, spaceman colour blind song). It was good the first time around , but watching it back and the boring parts last too long in order to give Brent the chance to floor people with some outrageous comment or antic. Then I sort of realised they weren't even that funny - it was just because they were out of sequence with the setting. I might watch series 2 later this week but after series 1 I just couldn't be bothered. Having said this, the christmas specials were excellent.
US Office is a simple sitcom that is like friends, you can watch them over and over which is probably what it is aimed at (the re-run market). It does suffer from a lull in episodes that aren't quite as good and introduced a lot more secondary characters to carry the show the six seasons. I always felt that Brent was so incompetent, impertinent and so shite at his job that it would be unrealistic to expect him to last so long (despite historic magazine awards). Michael Scott is off the wall and childish but you have actually seen him do his job well (i.e. sales and management).
Either way, it's just subjective anyway. Some will like one, some will like another. There is no right or wrong just preference.
