Digital (ly temperature corrected) TCXOs can deliver better long term statistical results while using cheaper crystals so they are becoming the majority on the market?
Analogue correction is smoother and causes fewer glitches although ALL crystals and both mechanisms exhibit some flats and steps when the load capacitance is adjusted.
The combination of a slow changing analogue reference and then external correction of a synthesiser via a GPS routine is Probably the best value for money solution?
Bruce Akhurst