I bought my ER6F in June 2008 and started to use it seriously for commuting from September onwards. As a 16,000 mile a year rider and this being a budget bike perhaps I expected too much, but it is supposed to be a commuter special. It's been plagued with problems: 2 sheared exhaust joints (common problem - poor design and vibration apparently); collapsed rear wheel bearing (hair-raising en route to work), not covered by warranty either - wear and tear apparently; leaking front brake calipers - again not covered by warranty; failed electrics (regulators - another common problem) and loads of rust. I do ride through winter, but wash every weekend and apply liberal ACF-50, still it comes through. Have put black hammerite all over the rear , still comes through. Compared to the XJ6 I rode recently the engine is rough and vibey and it's not as light to handle.
On the positive side, it's easy to ride and for someone who is getting on a bike for the first time it inspires confidence. It filters exceptionally well in mean London traffic, thanks to great visibility, nimbleness and narrow width. It's also decent on the motorway as revs for 80mph are comparitively low. It's fun too, and as an intro to motorcycling it has provided a lot of thrills for the money.
Needing to rely on it for regular, long-distance, all-weather transport meant this bike, for me, was a mistake. The quality of finish and materials used is poor as evidenced by the reliability issues and abounding rust. For someone with less demands, and perhaps new to biking, I would recommend it. For anyone else, and on the recommendation of several breakdown truck drivers who get to know the bad bikes, Honda is the way to go. I will not be buying another Kawasaki!