I could write a book about this....I've been married to a non-citizen since 2004 and we've been married 6 and a half years now. Marriage got us off the non-permanent visa game of finding a student visa or a temporary work visa like an H-1B, and now he's a permanent resident. We have to pay a small fee every 10 years to renew now. It was a fucking grueling process to get through that. It involved putting together a whole binder to prove we were really married, an interview with immigration where we had to once again prove we were married. We also retained counsel for that and paid some feeds to the government I think in the neighborhood of $1k. Then, he only got a 2 year green card and had to go through the whole thing again 2 years later to get a regular green card, which cost another $1k in fees, required us to put together a binder of proof that we were really married, which included years of copies of shared bills, old driver's licenses, pictures of us together with friends and in different locations at different times, and then they made us make an even bigger binder of more of the same (It was 600 pages of shit by the time we submitted it), and with a second interview we finally got there.
From now on forever, we pay the fee every 10 years and we're golden.
Alternatively, we could sign up to go through another year long process with a $1200 price tag on it, and take the extra time and attention of our time to get through the next step for him to be a citizen, but his country doesn't allow dual citizenship so the other thing we have to think about is, is it worth it for him to give up citizenship to his home country or not? Especially since the only benefit he'd be getting out of it is the right to vote.
So yeah, since there's no rush, we haven't really decided its worth the time and pain and heartache and aggravation of going through this process a third time because we know how this movie goes and we're not sure it's worth the price of admission.