I've never been to YMCA but I heard that they "baby" them a bit much, like just kind of flicking water on their face rather than teaching them to be comfortable with submerging. One of my friends did classes there, and she submerged her kid because she'd done previous classes elsewhere and the teacher was like "Wow, please show me how you did that!!" - something that a teacher should probably already KNOW how to do.
But then again if your aim is to just get them into a swimming pool rather than to get them comfortable with submerging and being more independent in the water, maybe it is for you.
With Harry Wright, there is a progression - first splashing their faces with water, then when they are comfortable with that, teaching them to hold their breath under water, then when they are ok with that, letting them go for brief periods of time. All under the age of 1. But from what I understand about YMCA (never having been there myself, just hearing friends talk about it), there isn't that progression - they just stay at step one, flicking water on the babies faces...
Maybe it's different for different YMCA teachers or locations - but I just know that my friend was very dissatisfied with them, in the class she was doing...