Eclipse crashes on me or freezes up frequently despite using a quad-core brand-new laptop with 8gb memory. The UI frequently becomes unresponsive. Anything to do with IO such as opening files, having maven pull in a bunch of files, etc is horribly slow and usually causes the app to freeze.
As far as I know it doesn't offer variable suggestion, in IntelliJ you just type the first letter or 2 and it immediately suggests any variables you have in scope, I find this invaluable as it really speeds up writing code sometimes. Overall, I find it simpler whereas Eclipse is just kind of a free-for all where you need to make use of a patchwork of plugins to be successful. IntelliJ is written by one company so I just always get the feeling it has a better "engine" underneath it.
Half the developers on my team curse Eclipse and say they hate it but none have switched to using another IDE except me, the others are too set in their ways, I get the feeling its firmly embedded amongst a certain generation of Java dev's but if you're just starting out (I'm also pretty young relatively speaking) I'd recommend considering using another IDE.