Best high speed train Barcelona to Valencia?
Here's a good source to see what's available.
https://www.seat61.com/train-travel-in-spain.htm
Don't understand the question: there's only one company serving this route. If the question is in reference to which type of train... ALVIA and Euromed are both very similar to make any difference. Forget AVE because it's not a direct route, it goes thru Zaragoza, hence the reason for the ridiculously long journey. The rest (Regional, etc) are not high-speed trains.