Hello,
I have used in projects for RF design, an Colpitts(Clap) oscillator(434/315 MHz). The schematic containts as basic element a special transistor( P-select)....It has good gain, but is very hard to find a good and stable matching. But it works at aprox -10dBm, and 7mA current consumtion. As i know , using an mmic is too expensive, and there are problems like stability that are the same in both cases.(I think also the mmic has an transistors in the final stage).
So , my sugestion is to use an transistor,to have a good oscillator.
Good Luck
BR