There were two schools of thought when it comes to these two types of material, and it all boils down to personal preference. Nylon is great because it is lightweight and breathable, and breathability is a big plus when it comes to these types of jackets that have a reputation of being a little suffocating. The downside to nylon is that it isn’t as waterproof as vinyl, and if your little one is outside for long periods of time, their clothes underneath may start to get a little damp.