Hi Roff,
Did you include the 1uf cap in your simulations too?
At what level where the oscillations? 1mv, 10mv, 100mv, etc.?
I took a little time to look at the circuit from a temperature point of view, and
i can see that it works quite well indeed, as long as the two transistors are
'matched'. That is, a complementary pair. As long as the two base emitter
voltages track over temperature the circuit stays the same...same output.
The sensitivity is quite low too, about 0.2 or so.
There seems to be quite a tolerance for change of individual transistor
gain change too.