245 Suicune

Snarl is generally more preferable due to its significantly better energy gains, though Ice Fang can provide useful coverage against common typings.

Bubble Beam is recommended for its low energy cost, in addition to its guaranteed ATK debuff. Hydro Pump is more viable with Snarl's fast energy, and takes advantage of STAB to potentially OHKO opponents. Ice Beam can provide useful coverage, which can be more valuable depending on the format. 

Suicune is a relatively tanky Pokemon, and with a mono-Water typing it had difficulty standing out among the very populated Water-type picks. The September 2019 rebalance gave Suicune the moveset buffs it needed to climb up the ranks, with fast energy from Snarl and guaranteed ATK debuffs from Bubble Beam giving it some utility. Additionally, extra coverage from Ice-type moves are welcome tools which may be useful depending on the format. While accessibility might be the main drawback in its usage, only time will tell if it'll shake the meta. 

Suicune's good bulk and excellent movesets are fantastic in dealing with the Giratina-centric meta that overshadows the Ultra League. Access to Ice-type coverage is valuable for dealing with common Dragon-types, while Snarl's fast energy and the debuff utility from Bubble Beam can make significant impacts if applied on important targets. Even for matchups that Suicune does lose, leaving the opponent debuffed could enable follow-up farming plays to turn the tide of the fight. 

With a max CP of 2983, Suicune struggles a bit in Master League in terms of stats. However, Ice Fang and the debuff ability are key to keep its relevance here, allowing it to munch through many big Dragon- and Flying-types without having the unconvenient weaknesses of a true Ice-type. In fact, with Grass and Electric being uncommon here, Suicune can hold its own against a variety of threats.