Vinegar and water. My husband gave my son cup a regular cup of milk once, which promptly got dumped on the couch, which then sat in the sun light and stunk to high heaven by the time I got home 6 hours later.
My couch is dark brown microfiber too. The cushions don't come off. Spray (like really saturate it) with 3/4 white vinegar, 1/4 water, and let is sit/soak in overnight. Blot as much as you by pressing firmly with a towel (this takes forever, but it works)... I stuck it outside for a few hours (it's a sectional, I just took that piece off) so it gets some fresh air, and give it a day.
It won't smell like puke, milk, OR vinegar, didn't stain, you can't even tell where it was!!