I've used them a few times. The last two times I used them, the flights had been subcontracted to Wamos Air, which run a fleet of very old planes with no entertainment or food included. They're always very cheap though, usually take off and land on time and I've never had problems with legroom, which is all you can ask for from a budget airline tbh. It blows my mind how so many people will happily pay 1-2k extra for a better airline, still flying economy, which often simply amounts to better in flight entertainment and some free (bad) food. Fair enough if you're utterly loaded, but assuming you have a regular income, paying a huge amount extra to fly with a slightly more premium airline is madness, IMO. I'd rather save my money and spend it on the hotel or things to do at the destination.