Is AdSense good or bad?

It's good and the reason is that it will encourage many smaller information rich sites to grow and provide even more valuable and interesting content for web users. In the past many really interesting sites have been posted by topic enthusiasts and the process has cost them money, particularly in the early days when domain names were expensive and so was hosting. Even now though, to post and host a decent website takes cash and it certainly takes time. So these enthusiasts were typing away with no reward save for a growing guest book and increasing site traffic (or not!). AdSense empowers many of these sites to make a bit of money and recover their costs or even make a profit. And there's a loose sort of equation too - more interesting and valuable content = more AdSense payouts.

Therefore whether you like the idea of making money from your site or of getting excellent informational resources online, AdSense is good.