I'm not sure how to feel about Drifloon. It has many good things going for it on paper, but in practice, some of them seem lackluster. I want to focus on the sets it can carry to sustain myself while explaining my point of view:We all know how decent Calm Mind sets are, enabling Drifloon to wipe and clean teams thanks to the Thunderbolt + Hex coverage it has, specially with trapper support from the likes of Trapinch and Diglett. The main reason for its success is how easily Drifloon can be put in hyper offensive archetypes with Toxic Spikes Mareanie, as it gives Drifloon a mean to status the opposing team in order to further improve its capabilities at sweeping the opposing team. Usually, Substitute can be used on the sets, but I only see it as a waste of a moveslot, when Will-O-Wisp helps Drifloon offer more utility than Substitute does. Even both Memento and Destiny Bond are amazing options, as jake mentioned before, offering useful tools to Drifloon in order to beat several Pokemon after it can't keep up its role. However, Berry Juice being triggered only once means that the Drifloon user has to consistently play their cards in order to enable Drifloon to be a threat, meaning that if the opponent has an answer to it such as Munchlax, you are forced to switch out and hence lose both Unburden and Calm Mind boosts. Knock Off is also detrimental, making Drifloon lose its recovery and force it out by the threaten of it, although some offensive sets carry the very niche Weakness Policy (s/os 067 the Hero) to instantly boost up Drifloon and allow it to break teams effortlessly.Thief sets are the best alternative to those Pokemon that Calm Mind cannot beat such as Munchlax, providing utility to its team by removing Munchlax's Berry Juice and inducing status with Will-O-Wisp, making the set be a dissruptive Pokemon for the opponent. Knock Off does not sound as an issue here since Thief can steal a potential Berry Juice or Eviolite, but this set keeps having a heavy reliance on Berry Juice to keep working. However, both Destiny Bond and Memento are moves which further enhance this set to be even a bigger threat, thanks to the offered defensive utility with both Thief and Will-O-Wisp. You can choose whether to exploit the status induced with Hex or deal consistent damage with Acrobatics.With all of this in mind, it is quite hard to find a fitting answer for all the versatility Drifloon offers, having to use conventional options to handle all of them or break through Will-O-Wisp sets with brute force. But if I had to offer my insight on what the best answers could be, it would be these three:Pawniard's role of soft Flying check comes in pretty handy when you can handle both sets thanks to its decent bulk and ability to setup. It struggles a bit with Calm Mind sets if slightly damaged, but can put the Drifloon user in danger of getting hit or being used as setup fodder.Onix is probably the best offensive answer there is to Drifloon, specially Sturdy and Weak Armor sets that carry Dragon Dance, as Rock Blast allows to break Substitute and outspeed Drifloon, which is even more noticeable on Weak Armor sets which are bulkier and withstand Drifloon better, while Sturdy sets offer a second life to set up and beat Drifloon.Encore Spritzee is a very good defensive answer to Drifloon and had seen usage in one game of Ekans , completely halting both sets thanks to its bulk. However, that would mean giving up other useful options in Calm Mind and Aromatherapy, as once it stops Drifloon, Drifloon is forced to switch into an answer to Spritzee.In summary, while Drifloon is hard to face, there is enough reliable counterplay to be explored that can make Drifloon not look as threatening as it should be. For now, I am undecided,after experimenting with Drifloon, so I would like more people to offer their view on the topic.