I picked one of these up from Homebase today, where for the purposes of price comparison it is currently £[]. Everything apart from the handles came assembled. A few nuts to tighten and I was ready to get going. It managed my small lawn quite manfully. It was the first cut of the year so the grass was quite long. I had to push and pull it backwards and forwards a couple of times to literally plough it through the longer grass, but it really wasn't hard work. Once I was through with the longer grass, it literally glided through the shorter grass.
As far as I can tell this model is exactly the same as the 300 model, except that this one has a cutting edge of 38CM rather than 30CM. It seems pretty robust and well finished. The grass box seems a little flimsy compared to everything else, but it doesn't really have to do very much apart from sit there and collect grass. The grass seems to go everywhere a little and not always in the grass box, but no more than any mower I've ever owned. Height adjustment is flexible and just involves loosening a couple of bolts. Similarly if the cutting edge isn't quite "cutting it" you can tighten or loosen a bolt as required. The mechanism that drives the blades is very highly geared, and only a small push of the mower sends the blades spinning for several seconds after you've stopped pushing.
I found mowing my small lawn with this unit very satisfying. The grass was left very neatly "cut" and not "torn" like with my old Flymo. Based on my experience so far, I would describe this mower as a good quality product that is very practical for smaller lawns.