I think they are all pretty much the same unit. I don't know if any of the oscillator models is any better. I assume they are all equivalent and actual performance (like any OCXO) is luck of the draw. Those boards run on 6VDC. The Trimble units use a 5V oscillator (which lots of places that remove and re-sell them say are 12VDC devices... surprise, surprise, surprise. The equivalent Symmetricom boards use a 12V oscillator and a DC-DC converter to run them off of 6V.