Leavanny
Availability: Early Game, Route 20, 35% Stats: Solid overall. It has high Attack, with enough Speed and bulk to get by. Typing: Grass/Bug provides some useful coverage, but also resisted by 4 types. It's also a lousy defensive typing. Movepool: Bug Bite at level 8 gives it a good STAB move early on, and X-Scissor and Leaf Blade give it power late game. Unfortunately, its movepool outside of its STABs is poor and provides mostly unhelpful coverage. Swords Dance is available for sweeping. Major Battles: Sewaddle's best match-ups are against Clay, Marlon, Burgh, Caitlin, and Grimsley. It can contribute against all of these, but must be wary of its weaknesses. Sewaddle does well against Team Plasma's Dark-types, but tends to struggle a bit against their Poison-types. Additional Comments: Swadloon evolves into Leavanny with high happiness. Although this means that you can't predict when it will evolve, it should evolve fairly early.
Virizion
Availability: Late Game, Route 11, Stationary Stats: Virizion's stats are a bit unusual. One should take advantage of its great Special Defense and mixed offensive capabilities coupled with its great Speed. Typing: Grass/Fighting is a bit subpar, but grants Virizion good matchups during the late game, as well as solid STABs. Movepool: Virizion comes with Sacred Sword and Giga Drain. It learns Swords Dance at level 49 to give it a needed boost for Sacred Sword. It can be tutored Seed Bomb for another physical STAB. Return can help out with coverage. Major battles: Virizion can struggle a bit against Drayden, especially if it doesn't get a Swords Dance boost. Marlon should be an easy win, as should Grimsley. The rest of the Elite Four are matchup based.
tldr Virizion is better. source This source is outdated and a little bit inaccurate, but if it ranks Virizion in A and Leavanny in B, the chance that Virizion is better is still pretty close to 100%. Just in case you're wondering, you can see the newest thread here.
