As an entry level D3100 user, I can say this: I have several friends that are professionals in the field, and each of them had nothing but good things to say about the camera. Also, in the class I'm currently taking, the instructor is always pleasantly surprised by the quality of the photos.
Are there better? Do others have more options/features? Yes, quite a few, but you won't suffer at all by learning on this camera. It's the skill of the photographer, with DSLR equipment, that often makes the difference in good or bad shots, and this camera gives you access to manually adjust the "big 3" settings everyone needs to learn before dabbling elsewhere.
If you've got an open budget, and you're sure this is going to be a serious, long term venture, go for what you can get!!! Don't be afraid of this camera, though, because of the "entry level" tag. It's a phenomenal camera in its own right.