I agree with Matthew K. Their accent is quite different from ours. The more you go to the northern regions, the more different is the accent. If I'm not wrong, the variant of Lisbon if closer to ours (especially the one spoken in Rio de Janeiro). Besides, it's sometimes difficult to me too to understand what they say! =P

The accent is really different, you can check it out on Youtube. Some expressions are also different, but it's no big deal. So yeah, you might have some trouble with the accent. I speak Brazilian Portuguese and I find it difficult to understand the European accent sometimes. Cheers!

No, there are some differences in writing and in speaking, but you can easily understand both variants if you make some effort. You have dozens of different accents inside Portugal, Brazil and the African countries. Don't limit your study to one of them and feel free to ask for help.

It's very different, like british english and American english ^^ like Itamar told, we had a lot of influence by other cultures and I'll put other culture that he don't said, the spano habalantes (Argentina, Chile, Bolivia...) they are so close that their culture have influence in ours and our have influence in theirs

Hi. There are some differences: accents, word, way to speak. They use the same gramar but in different forms. Ex: Eu estou estudando Eu estou a estudar. ok?