Hi, I judged moved back to the US after 11 enjoyable years in the Netherlands.
If you don't already have the right to work in the EU, you will find it extremely difficult. You might be able to find work if you are in a very sought after field like software, but still not likely.
If you do have the right to work in the EU, then your chances depend on your education and language skills. If you are a white-collar professional (engineer, accountant, etc) and you speak Dutch and one other language, your chances are very, very good. If you speak no Dutch but do speak English well, your chances are still good.
I am an accountant who is a native English speaker. I never got to,learn much Dutch (could just do shopping in Dutch, get around and have polite, short conversations) and I got contacted by head hunters in Rotterdam frequently. More than Amsterdam, really.
Amsterdamers consider Rotterdammers "rough," but on the other hand, Rotterdammers consider Amsterdamers snobby - more style than substance. The stereotype is that Amsterdamers talk and Rotterdammers do.
Rotterdam is a great city and much, much more affordable than Amsterdam, It also has plenty of style and funky places to discover. I would not call it rough, though both cities have their rougher neighborhoods, like anywhere else.