For shoes in general I vastly prefer leather for the breathability, stretchability, and overall comfort. If I'm buying a pointy toed pump, you better believe it will be leather, as I need to stretch that baby around my bunion foot!
I'm not sure leather shoes wear any longer or less -- I am sure good leather requires maintenance to last longer. Time between wears to dry/air out, water repellant treatment, wiping down salt, frequent cobbler visits, leather cleaner/ moisturizer.
Non-leather requires less maintenance. You should probably still give it time between wears (non leather gets stinkier faster, because of less breathability). But you may not need to water repellant treat it, or wipe it down for salt, or use special cleaner or moisturizer on it.
In practice:
Leather:
I have a pair of wine boots that are going on 15 years strong.
My black leather boots are 10 years old and still look new
Non Leather:
I have 12 year old boots that are completely and undeniably synthetic looking if you look close... these are the boots I drag out when the weather is most sloppy and salt filled everywhere. I don't wipe them down every use. I have treated them rather poorly -- yet... one wipe of a damp cloth and they look new again. I am afraid to throw these out because they will probably last 1000 years in a landfill! They've never even needed re-soled or any cobbler attention.
I've also got a favorite pair of synthetic leather booties that are a few years old and have worn quite well. The heel tip needs to be replaced, and the pointy toe is just starting to subtly fray a bit. I'd replace in a heartbeat as they were definitely worth the cost per wear.