I fly the 429 and the 135.
Vibration: 429 is generally a smoother ride
Noise: 135 is noticeably quieter in the cockpit and cabin.
HEMS suitability: 429 clamshell door design prone to problems vs 135’s simpler design. 429 less accepting of off airport landings due to very low damage tolerance skids. Limited visibility through 429 chin bubbles can be an issue during confined area ops.