they got the hours, the experience, passed their assessment, OPC, Line checks, that's what matters!
Truckflyer, you're kidding. Right? I think Callsign Kilo is right about Lion Air, the dangers (literally) of flying with them, and a pilot's employability after gaining 500 hours with them. There will always be exceptions - people knowing someone who had a great experience at Lion and now flies for a major airline, but....
A group of Lion Air cadets did their type rating alongside us at CAE in Amsterdam a few years ago. They were taught (what seemed like) similar stuff, by the same instructors (IIRC) and seemed intelligent guys. Criticisms of Lion Air are not criticisms of the abilities of the cadets. But 500 hours of flying with insane Captains in marginal weather in a poor crm environment is not 'good experience'.
I also have a friend who went there and he said it was terrifying flying for them. He was ill, lost his medical and then got dropped by them. You see, it doesn't matter how 'good' you think the raw product coming out of the TRTO, it's what happens on the line that matters.
Contrast Lion Air's reputation, blacklisting and basic terms and conditions with Ryanair and you can see why FR has an excellent safety record (touch wood) and provides pilots to many major airlines.
Go to Lion Air at your peril.