With the Z5 also running impressively quietly, showing motion adequately clearly and smoothly, and using its LCD technology to steer clear of the rainbow effect problem that blights budget DLP projectors, you're probably starting to wonder why the Z5 only has an overall mark of 7.
The answer lies in those same black levels I was praising a moment ago. For while the Z5 certainly can go darker than any other dead cheap projector, that darkness comes at the expense of an uncomfortable amount of brightness. For instance, while the black bits of Barbossa's cave in Pirates… might appear relatively free of greyness, the piles of gold and precious artefacts lack their customary lustre, looking muted and bland thanks to the extent to which the Z5 has had to reduce the image's brightness to make black colours look, well, black.
Closer inspection of this scene also uncovers a problem whereby although dark scenes look surprisingly black, they also look rather flat and hollow thanks to the amount of subtle shadow detailing that's been consigned to oblivion by the Z5's automatic brightness reduction. You can, of course, manually adjust the image so that it looks generally brighter. But that merely introduces the dreaded grey mist effect over dark picture areas.
The bottom line here is that despite spending an eternity tinkering with all the image adjustments the Z5 provides, I never got a balance between contrast and brightness that I felt wholly comfortable with. There always seemed to be a scene or two in anything I watched that suddenly looked distractingly dark or distractingly light, depending on how I'd got the various contrast-based features set.
Let's not forget, either, that I was experiencing this in a completely blacked out test-room environment. The Z5's tendency to bludgeon away brightness during dark scenes could make pictures really quite hard to watch if you have even a little ambient light in your viewing room.
One other much smaller niggle I had with the Z5's pictures was that they didn't deliver particularly sharp or highly detailed HD images. You can certainly easily see the difference between HD and standard def sources, but there's not that jaw-dropping snap and sparkle witnessed with the very best HD projectors around. But this is probably no more than you might expect given that the Z5 only costs £700 these days.
My hope with the Z5 was that I'd stumbled on a true budget gem; an aging but good mid-range LCD projector made irresistible by having its price reduced to bargain bucket levels. And actually the Z5 gets frustratingly close to living up to that hope, showing signs of genuine quality that you seldom get on projectors that have been built from the ground up to hit a £700 or lower price tag. In the end, though, the inconsistency of the Z5's brightness/contrast balance distracted me just that bit too much for comfort.