You will love it. The language is pretty much a version of C, so if you're used to Java/JS you should have no problems. The core language is pretty standard, but you will want to peruse the Libraries section as well as the Playground.
Right now, I'm playing with the tvout library - requires two resistors, that's it... NTSC composite video out. I used it for a video "greeting card" for my wife, and am using it for an interface for several projects. LED's are cute, but for less money and code, I plug into a portable DVD player's screen for 16x12 text and 128x96 graphics including primitives. Very cool in my book! Even better when you are driving a bigscreen off your little 'duino... hehe. New version of the lib supports nearly twice the res... I may port a bunch of the OLDE TYME games over for giggles. I have (yes!) an ORIGINAL copy of DEC's PDP game programming book sitting on a shelf.. WUMPUS and others come to mind. I wonder if MORIA or LARN would fit...
The hardware is great, the language and IDE are great, and the community is very cool too. Some microcontroller websites are kind of unfriendly, you won't find that here.
Looking forward to seeing your first project!