We used Transavia in October 2025 to fly to Paris from Seville. It was a typical Airbus 321neo similar to the Delta, KLM and Swiss Air planes we used in 2025. Premium seating didn't really obtain anything too substantial aside from earlier boarding and quick exiting. We still had to check our carry-ons due to weight exceeding policy. However no one actually checked it and people brought some onboard that were clearly heavier than ours. The flight was on time and uneventful. The only problem we noted was late opening of the baggage check-in counter and LONG line and wait. We hustled to boarding!
We had a fine experience on a similar Swiss Air flight from Zurich to Barcelona with a nice salmon lunch in first class. We still had to check our 23 lb. carry ons. The plane seemed new due to it's exceptional cleanliness. The Transavia appeared well worn in comparison. Swiss Air definitely handled baggage check in efficiently and early enough to allow us to relax.
KLM was the only inter-country flight that had long delays for their own reasons - waiting for a part that was needed to repair another plane at our destination. We waited for several hours after boarding the plane at Amsterdam before finally arriving in Zurich. We actually watched the delivery of the "part" and loading underneath our window.