Nokia gave Om Malik a bad unit of the N81 because he just wasn't impressed with it. He says the S60 is way slow... like 10 seconds to open a text message and a lifetime to go from one app to another. It's very difficult to fall in love with Nokia's next big release when it's janky.
The device behaved like a three-year-old throwing a tantrum. Unless this is an especially buggy device, N81 has to be one of the worst Nokia phones I have ever used and would be loathe to recommend it to anyone.
He did mention music playback was very good, but the N81 is definitely the worst Nseries or Nokia phone he has ever tested. If you ask me, it's a good heads up for Nokia, who are going to launch the N81 in a few months time.