I've been on Shinkansen, Taiwan HSR, and TGV.

I did not like TGV because the seats lacked legroom on standard class, as uncomfortable as airplane economy for me. Did buy in advance and was cheap(ish) though.

Shinkansen, I've been on it many times because I live here. It's excessively expensive if you buy on local prices (no rail pass eligibility for residents). It's comfortable in any class, frequent beverage and food service thats reasonable, and city center service. Having said that, bought a few days in advance, ANA is the same round trip price to Osaka so I'll choose that for *A mileage credit as total time door to door is quite similar. Other places in Japan are more expensive to fly than Osaka typically.

Taiwan HSR, same trains as Tokaido Shinkansen, but very cheap in comparison. I like this train very well except the stop nearest Taoyuan Airport isn't serviced by all trains and if you're not closely paying attention it's easy to end up in Taichung and miss your flight.