Anyone who has/knows about a Nikon D3100?

I have decided to buy this camera… But I would like to be 100% sure.
What is good about it? Bad? Any tips or tricks? Anything else?

There are 1810 answers about D3100s on YA. If you are too lazy to read them, I can't be expected to help you.

I haven't actually use it but based on reviews and the specifications of that camera. It's a best buy. If I will be buying an entry level camera, I won't think twice, I will buy it.

It's a pretty general beginners camera. Although you really should just look it up on a camera review site, or maybe CNET.com. A tech review site breaks down most of the camera for you.