I currently have one (older) gravity feeder. It tended to require more maintenance than my timed feeders - always clogging or becoming a birds nest it seamed. It had this style of tube (a 4-way?)
I have seen several other tube styles (such as the one boss buck uses (3-way?), and the several used by allseasons (they have one similar to the picture, and a different style used by the evolution line)- but have no idea how they compare. I have seen recommendations for snorkel tubes, but do not know what that refers to.
Anyway, it is time to fill up the protean feeder, deer are hungry. Looking for suggestions (what to buy/get). I will probably try to continue to use the old one, but would not mind getting up 2 more. Did see a suggestion for a manufacturer out of Georgetown (who give the options between 3-way and snorkel - great...). Cost is always a consideration - but I know better than to think I will be out every weekend to check on it, so it really needs to be lower maintenance than that (low maintenance>low cost). I put up a 1k corn feeder this year and it was really nice only have to fill once during the season.