It might be worth playing on both and seeing which feels better though. Buying the Yamaha and then finding out it plays like a brick with cheese wire might piss you off a bit after forking out $100.
This. A million times this. Always play out any guitars you're considering, to be sure it feels right, the neck feels good, it feels comfy when it's hanging on you, that you can sit down with it comfortable on your leg, that you can reach higher frets more easily, that there aren't knobs or screws or anything in places where you might normally anchor your pick hand, etc.
Also, take your amp with you (the 15x is fairly small, IIRC) and play the guitars through that. If that's the amp you'll be playing through, you wanna know that not only does it feel good in your hands, that it sounds good through the amp you'll be using. If the guitar shop wants to make a sale, they certainly won't mind you bringing your amp in.