It all depend on what your looking for. Both have different way of building. Both will chuck the clouds. It comes down to preference. I have both.
Avocado has a warmer vape and I wouldnt recommend to lay it down on its side for a long time. When I travel with my gears, the Avocado has to always be empty before storing it in my bag. Also, no matter what anyone says, you need to learn how to do the Gene lean to use it.
Griffin wont leak when done right, even if you leave it on its side for a week. Filling it is a breeze also. Easy to replace coil builds when you think its not working out even when its full. And whatever anyone says, you will always get a better flavor from bottom airflow and thats a fact.
I use my Griffin more because I dont have to think about it as much. Like I said, it all drops down to your preference.