I've never been to either and am wondering what the difference is? I'm sorry but I'm not even sure how far apart they are.
We are late 40s, like to walk the beach, check out the town, don't need much of a night life. I do dive and love to snorkel but that's not a priority on this trip. We just need to relax and decompress.
We are planning 2 weeks at the end of January.
I'm looking at the RIU Emerald Bay in Mazatlan or the Tesoro in Manzanillo.