AOS - cannot leave the country until receive green card. can request permission to leave but it's my understanding there needs to be a good reason. they also cannot work until receiving green card. if she enters and you get married be prepared that your application will come under scrutiny as you're asking if you should commit visa fraud since a B2 is a non immigrant visa and they are entering with intent to immigrate. consular - yes they can still visa on their tourist visa. just need to have evidence of ties to home country so they don't deny entry on suspicion of immigration intent. positive is that she can keep working in her home country and can leave and come back again. also once she receives her green card she can enter and be able to go back to her home country without requesting permission and will be able to work immediately once she arrives. as far as I seen, both take around the same amount of time.

I’d like to add and clarify a few things, and only according to the experience on applying while the foreign spouse is in the states. 1. Petitioner (US citizen) needs to file I-130 Petition Alien Relative for the beneficiary (foreign spouse) 2. Applicant (foreign spouse herself) needs to file I-485 Adjustment of Status, to change her B2 status to be registered as permanent resident. Here’s a link that might help with how you plan with the timeline, since coming in with B2 and getting married is tricky, but not impossible (if possible, do more research so you don’t just make decisions based on our comments/suggestions here, because each person is different): https://www.visapro.com/resources/article/getting-married-on-a-tourist-visa/ 3. Applicant (foreign spouse) needs to file I-765 Employment Authorization Document (EAD) if she wishes to work before her Green Card’s approved. It is correct she can work with just the Green Card, however, in most cases, EAD has shorter processing time than the Green Card. Once she gets approved for EAD, she’ll get the SSN (if you mark on the form that she would like to receive a Social Security card), or if not, free you get the EAD, go to the Social Security office to apply for one. (I’m unfamiliar with getting the card with the I-765 application, learned it from other posts, so please double check.) 4. Green Card applicants are required to remained in the United States while waiting for approval and before having the card in hand to travel with it and without any type of visa, however, like EAD, she can file I-131 Advance Parole, to temporary leave the country and be able to return before getting the Green Card. The processing time is also usually shorter than the Green Card. Now after re-read your post, and from my understanding, entering with a B2 with intention of getting married during the stay would create serious problems (if you read the link I put above, you’ll learn that). It’s always best to be honest while dealing with immigration related questions, so perhaps do some research on the other option to go through the Consular Process and see if that fits to your needs and eliminates things that could go wrong. Good luck and hope it works out.