I upggraded my gliding licence to a PPL A last year und was flying the 150 most of the time. My flight instructor uses the 150 for students who have glider or microlight experience, for absolute beginners he uses the 172 because it is more stable and much easier to land if the wind is stronger, gusty or cross. It also has a much shorter flare which seems to make it easyer to beginners.. .If doing cross country flights and not just collecting hours, the 172 is the cheaper one due to the much higher cruise speed.. .Try both and decide for your self which one feels better.