As an organization, ISRO is political and bureaucratic. I have a good "set of friends and family" worked there or working there. There are good people and bad people (projects) there. You must be lucky to get into the right one. The pay scale is not competitive - But its not worse. The perks are really good. i.e Ultimately they get paid a little less than a private cos. The perks from the governments should not be discounted EVER. I work in a private co. which is much better than the Infosys/Wipro/etc s.w co's (also with a relatively much better pay). But I can tell you, ISRO job is better than mine. If I could opt today, I would go to ISRO.

With a little lesser pay, you also get peace of mind. This might not be important at 22s or 25s. But at 30, as a husband and a father, I can surely tell you ISRO gives much better lifestyle. i.e you can work for 2 hours or 16 hours if you enjoy that. Average employee productivity there sucks - literally. But at that non-competitive pay, government should not expect more.

You also have a "safe-job" and lesser work pressure. There are certain projects that are high-pressure jobs - but those are rare.

An important factor to keep you motivate might also be "working for your country". I have worked for large govt. projects for western countries and it give you ZERO sense of pride. It is "just another project". And I worked for a very small system for the transportation in my city. And just that feeling of watching that system being used in my country gives me a hell lot of sense of pride/achievement. I don't know if everybody feels the same way - but that is one of the biggest motivation factors for me (I don't work for ISRO / govt)