It is not a "good" oscillator, in the sense that it does not guarantee that it works.
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If I understand it correctly, it depends on the zener-like reverse breakdown of the transistor's base-emitter junction.? That is something they do not guarantee, because 99.9999% of circuits neither exploit it, nor allow themselves to approach breakdown.? Many transistors exhibit that breakdown, in the range of 5 V or so, but some do not, or behave differently.
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Grab a handful of transistors, with different part numbers, different manufacturers, and different manufacture dates, and try them all.? Some might work better than others.??There is probably a way to enhance the effect but I don't know off-hand.? Perhaps adding a large resistor from collector to base might help add to the leakage current.
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My personal advice is to stay away from circuits like that.? If they work, you got lucky.
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Andy
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