The first ten chapters are an slow (but not worse) introduction about what will come and what this manga is about. Excellent narrative and drawing, and the history have some interesting surprises. Just one warning: is a +18 manga because of a violent scenes. Anyway even if the violence is there, the manga it's not about that. If you are not very apprehensive I suggest you give it an opportunity.
At the begining is more like a entertaining shonen but nothing more (in my opinion, of course), but as the history advances and it transforms into a seinen, the quality grows and grows. Today I can say that this manga gave me one of the best manga chapters I ever readed (52), and I just can't wait to read more about Vinland Saga.