Hey!
A lot has changed since I played reborn but here are my thoughts on the pokemon I used during my journey!
Yamna/Yamega
Rank: B
Availability: Shortly after Kiki and halfway before the fourth badge.
Ability: Tinted Lens, Speed Boost
Movepool: Relatively shallow: Air Slash, Bug Buzz, U-Turn, Detect
Comments: Yamega is an absolute beast of a bug type. it has pretty good stats but what really defines it is speed boost. This lets yamega outspeed any pokemon in combination with detect. Even though yamega might not have the best coverage in the world it has what it needs to work. Bug buzz and air slash works as powerful STABs, detect compliments speed boost, u-turn is nice for chip damage, it does get ancient power but i personally don't like using it. Yamega does incredibly well versus Luna and Samson able to outrun all their pokemon and wreak havos with its STABs. But despite this yamega has one huge glaring weakness. it doesn't get a single its STAB until level 45, air slash. Up until then you're stuck with uproar I believe, making yamega pretty useless. So while you get yamna after Kiki you it won't be any help until you get to Noel. If you really want to use yamega I would recommend you train it durng the period between episodes, don't keep it on your main team it's simply a burden that way.
Espeon
Rank: B-
Availability: After fourth gym.
Ability: Magic Bounce, Synchronize
Movepool: Poor: Psychic, Morning Sun
Comment: Espeon isn't a bad pokemon. it has fairly decent stats, pretty good special attack and speed and reasonable special defense. it also gets access to Magic bounce which deflects any status or debuffs thrown at it. Unfortunately, this ability isn't as good as it sounds...... Battle in reborn rarely ever throw debuffs or status conditions at you during the stage where you get espeon. In fact ever since I got my espeon a year back I can count the amount of times this ability was used with my hands. And unfortunately outside its stats and ability espeon has very little going for it. Its movepool is shallow, limited only to psychic and its other ability is just as bad as Magic Bounce. And another issue, espeon gets outclassed in every way by gardevoir: gardevoir has a better typing, gardevoir has a MUCH better movepool with access to calm mind and moonblast, gardevoir has arguably a better ability. I use my espeon mostly as a calm mind sweeper but since the tm for clam mind got removed a long time ago this isn't even viable anymore....... Espeon is a workable pokemon but just be warned it doesn't have much going for it and it get outclassed by other psychic types. Oh and it really does well versus Samson, its ok at most other battle but that the only one where it stands out.
Pinsir
Rank: C
Availability: after sixth gym.
Ability: Moxie, Hyper Cutter
Moves: Decent: Swords Dance, Superpower, X scissor, Storm Throw
Comment: Put down those pitchforks and let me explain. Pinsir honestly isn't that bad of a pokemon. It actually has pretty nice stats. Very high attack, decent speed, and quite nice defense. It's move pool is also fairly good: X scissor for STAB, it gets quite a few fighting moves for coverage, and it gets Swords Dance to break walls. It also has a fantastic ability in the form of Moxie which lets it off set the attack loos of superpower or run through entire teams with X scissor. It does amazingly versus Luna, able to tear holes into her team with moxie boosted X scissors and Superpowers. Unfortunately despite this no one will ever use pinsir until the mega comes out because it had the misfortune of being placed directly front of version 2, heracrosss. Also the event to get pinsir is INCREDIBLY long like i've done it twice and both times it took me a few days to finish. Overall yeah pinsir gets outclassed pretty but that doesn't mean it a bad pokemon.