I´ve been using Shimano A11 for long time now. It has about 12000 km on the clock. Works fine, shifts perfectly. In the beginning I had issues with leaking oil which is a common thing. I decided not to use oil but went to light grease with spec. NLGI 00. Doesen´t leak anymore and works fine. I do the gear maintenance once/3000-4000 km or once a year.
You could use any of those options, but they will all absorb more of the input energy compared to traditional chain and derailleur gearing. This will reduce your output speed or distance by comparison.
Priority Bicycles offers both a Pinion Gearbox Road Bike with a 600% gear range and a CVT Road Bike with a 380% gear range.
I recently purchased the CVT and find it suits my needs. I have on occasion wished for both lower and higher gearing availability but generally I'm not climbing killer hills or trying for speed records.
Sequential gearing (or gear ...