I've been riding 20 years and have had over 200 bikes. The FZS600 is one of the best.
The engine is a gem, lots of mid range and real kick in the pants when the revs get above 9K. The front brakes are awesomely good, the back is a bit poor but then who uses the back brake anyway?
The handling is very good, helped by the low all up weight, if it has a limitation it's the standard rear shock which can lose a bit of damping when it gets hot. A Hagon would sort it but it's not a sufficient problem that I've done anything about it.
You need to keep an eye on the oil level, it only holds 3 litres so a little loss can make a big difference to the oil level in the sump.
The fuel economy is excellent - I don't know where MCN got its figures from but they are plain wrong. I just got back from France, 900 miles fully loaded up, 80 to 90MPH most of the way and the bike returned nearly 60MPG.
The closest comparison I can make is to an old GSXR750 streetfighter, except that the FZS600 handles and stops too...
I've given it 4/5 for equipment because I wish they'd fitted a temperature gauge rather than a warning light.
Price wise these are similar to Bandit 600s, a bike which by comparison is fat, slow, wobbly and dull. Buy a Fazer and you'll be grinning from ear to ear :o)