i prefer it with the zoom ring on the front. especially with heavy lenses. better support and you can use your pinky and thumb for focus fine tuning i guess i just got used to it that way.
Same here, Especially with the 150-600, where you need to support it further from the camera anyway when shooting hand held. It takes some getting used to I guess, but its not as hard to master as the 100-400 push pull system where you keep overzooming the focal length you want.
Give it some more time and practice to get used to it - it will be worth it.