Yes it's a bit more expensive but the trains themselves are way more confortable, most of the time on schedule and drive at full operational speed all the time because they rails are made for it. With TGV on the other hand you have a few sections which are standard rails and thus you the train drive at a normal (low) speed...

More comfortable than the TGV? The train I'm most familiar with is the Thalys, the high-speed train from Amsterdam to Paris, and I'm not sure if it's more comfortable than other TGVs, but it's always a joy to travel in.

I recently went to London in the Eurostar, and they'd managed to make the train experience feel like a plane. Very disappointing.

Having recently used both the TGV and the Tokaido Shinkansen, I'd say the Hikari line is much more comfortable than any of the TGV trains.

Regarding the Eurostar, it works like that because the UK is not in Schengen. As such, border control needs to happen. Not to mention the potential issues with terrorism. And the Eurostar is net inferior to any of the Shinkansen trains.

Can confirm, I've been on the TGV and also a few bullet trains in Japan - the bullet trains were practically luxurious in terms of comfort and space, and the service was fantastic.

I also found the bullet trains to be great value, especially when compared to the expensive, uncomfortable, over-crowded, slow, dirty, late trains here in the UK.

The border checks absolutely added to the plane feeling of the experience, but Eurostar seats are also significantly more cramped than those of the Thalys.