I've got a metal one that I haven't tried yet. I've also got one of those plastic ones that holds the grease in the bottom and you lean on the top to force grease into the bearing. It works pretty well.
This is the best one by far.
i set it in my drill press and use the down force to press it. Drill press turned off of course. Cold shop and heavy grease. Those two funnel deals are messy and a waste of grease. I threw mine away after 5 or 6 uses.
