Thought I should add my experience here. I hadn’t flown UX in ages but tickets between Paris and EZE were absurdly expensive save for them, which were reasonable (this was in Y). A couple of points:

1. Overall positive experience considering they were the cheapest. All flights on time, bags made it with me, planes were new and clean, SkyPriority was acknowledged. Also I contacted them via Facebook because I wasn’t allowed to select seats and customer service was very responsive.

2. Definitely book a bulkhead/emergency exit seat as pitch in Y is terrible (this applies to all airlines on ULH flights such as Europe-EZE). IFE wasn’t great but also not bad (I did watch a pretty good documentary about Jerez wine) but note they charge 3 euros for headphones.

3. UX only offers 1 complimentary meal on the MAD-EZE route and FAs do a coffee and tea run before landing. Anything else is buy on board. Prices are fair (I think I paid 6 euros for a Coca-Cola and a bag of chips) but this seems a bit tacky considering it’s a +12-hour flight.

4. My main criticism is the lounge situation. UX uses AENA lounges at MAD which also admit Priority Pass/Lounge Key/etc which in my case meant that the Cibeles Lounge had a long queue of people waiting to enter when I got there. I asked if they prioritised UX C/Sky Priority and was sent to the back of the line. After 10 minutes queuing I just quit and went for a beer downstairs. No problems entering the Puerta del Sol (Schengen) lounge on the way back, though.

Overall I can’t complain considering the price, but my advice would be to avoid unless they are the cheapest option.