Well, SI gives you a ton of exposure because it allows you to reach far more people than Vogue (I'm pretty sure their circulation is higher, especially for the swimsuit edition). If you want to go fully commercial and potentially break into future markets (VJ-ing, acting), it's an excellent opportunity.
Anyway, re: Vogue (and Harper's, Glamour, Elle etc.) , it's been said countless times on tFS by model members that editorial pay hardly anything, especially after taxes and agency commission. In NYMag, an article last year said it was at most $250.
The thing is, Emily doesn't need that exposure, she's got great money jobs already. And it will be difficult for her because she is very commercial looking, which is unappealing to the high fashion crowd unless you're Doutzen Kroes.