I bought one of these as a stopgap a couple of months ago - e-bay £55.
I was a little wary at first as I didn't want to stick a 'poor lens' on my new D7000.
It took some getting used to - and my first shots (of wildlife at dawn, an owl, heron and some insects) were unusable (camera shake). Since then I've had some great results with it both on my D7k & my D40.
Between 100+200mm it's pin sharp. For wildlife, I guess it has to be a bright day for the best results, but I have taken some moths and butterflies with it which are as good as anything else I've ever shot. Also get some lovely bokeh while using the close-up-macro facility.
OK it's a bit noisy, a tad slow to focus, but as far as iq goes, I'm more than happy with it, and I reckon even at £99, if you give it a chance you'll love it too