I only use boge cartos on my Old goat bottom feeder.. they don't leak and it's super easy to bottom feed, plus I think it makes a carto last longer than top filling. I fill mine from the top for a day or two and then bottom feed it. My Old Goat works great and the button is very trigger happy.. I just have to be careful to turn it off when I'm not using it. It does tend to leak when using attys. No, it's not perfect but I'm so glad I bought it!
also.. I only use the boge 1.7 resurrector from crystalclearvaping. Anything higher in ohms is just not warm enough for my anymore. You can fill a carto, fill the bottle, pop in a fresh battery and you're good for all day. when you squeeze to feed the carto, give a quick suck to suck the juice up into the carto and you're good to go. this is as easy as it gets! (maybe it IS perfect LOL)
It's also easy to drip with a carto to change flavors. I do it all the time when I'm sitting here at the computer. Just drip 3 drips into the catch cup (with the carto attatched) and give a suck and the flavor you just dripped is the one that comes through. I do only use compatible flavors. I always keep waffle in my bottle and everything goes well with waffles.. I am currently dripping tastyfinger, caramel popcorn (all from tastyvapor) and some of my diy chocolate mix.
I also use a vv bottom feeder but I always keep my Old Goat with me cause it is so dependable.