Ouigo train Madrid to Barcelona?

I was unaware of Ouigo operating within Spain.

Looks like Seat 61 has answers:
http://seat61.com/train-travel-in-spain.htm#Spain_by_train,_in_a_nutshell

Look at AVLO high speed trains from Madrid to Barcelona, recently launched low cost alternative to the AVE.

https://avlorenfe.com/vlc/home.do?c=_aDZ4

On some of these trains, the cheapest tickets are in the old bar cars and have missing or misaligned windows—they were meant for standing at the counter and the windows are higher than the seats. I forget if it's Ouigo or Avlo (or both?) Not a deal breaker, but a thing to look out for.

Thanks everybody. Apparently the Oiugo service is fairly new in Spain. The post linked to Seat61 is really informative.

You can't reserve seats in the French bar cars.

Bets- SNCF ripped the bars out of the French Ouigo trains for more seating. I checked the Spanish options and oddly Ouigo left the bar there—first class seating too, sold as XL Seat. (Second class only on French Ouigo)

It’s Renfe’s low cost Avlo that has the misaligned seats where the bar used to be.

Yep, SNCF operates on that line — giving Renfe a little competition.

Same as Trenitalia competes with SNCF on the Paris-Lyon-Chambery-Turin-Milan route.

we used Ouigo from Barcelona to Madrid last week. First of all, and not comparing to AVE, the cars were packed. Every seat was taken (not especially important). Boarding was a bit of a mess - crowds getting on, people trying to change cars (after they realized they didn't know how to read the tickets for the "coche" number). Other than that, it was fine. The seats were comfortable, bathrooms available, and I understand there was a club car with food/drinks. I don't know if this helps. But make sure you reserve your seats in advance. There was nobody checking the size of our luggage or the number of pieces (the website gives the opportunity to pay for more than one piece of luggage or something like that). Good luck.