In my first playthrough of White( japanese version) I pretty much used all of my pokemon in gym battles, and I feel Elesa was the hardest. I mean, Emolga and Volt Switch is one thing, but AERIAL ACE? DAMN!
And Iris was not really TOO tough( at least when you use all 6 members of your team). I must say, my first playthrough had a bad lineup actually. Wehn I think about it, most of my wins happened because of my Throh! He's just so awesome, bide will just kill those pokemon and besides that, the attacks you can teach him are just wonderful. Plus my Throh had a special defence boosting nature! :D
Anyways, I'm going to list my recent Pokemon Black(English) Playthrough. I use the same number of pokemon as the gym leader does in each match:
Gym 1- Cilan
Pokemon- Lvl 12-14 Oshawott and Lilipup
No.of tries: 2
On my first try Pansage kept using work up and my Lilpup had low defence. He got knocked out in two hits. Oshawott DID deal with Cilan's Lilipup but... I think we know what'll happen here.
Then I had a rematch with Lillipup at a higher lvl now, say 14? Well, that was it, I won.
Gym 2- Lenora
Pokemon- Lvl 17 Herdier, Lvl 18 Roggenrola
No.of tries- 2
Ok, my first try was pretty unlucky atually. My herdier almost KO'ed her Herdier but Take Down recoil was too much to take. The my WTF moment- Roggenrola uses Rockblasst, misses, gets crunched but ok damage, then does another rock blast, which does a CRITICAL HIT! Watchog ALMOST faints and then it gets a critical hit with crunch! Roggenrola fainted.
The second time I had luck on my side. Herdier first criticals with Take Down to KO Lenora's Herdier, then Roggenrola just Rock Blasts Watchog out of the stadium.
Gym 3- Burgh
No. of Tries- 1
It was pretty cool actually. First Roggenrola takes down Whirlipede with ease, then Leavann comes out and KO's my Herdier and Dewott with ease, THEN my roggenrola takes a razor leaf hit with minimum damage and KO's his Leavanny, and finally KO's his Dwebble. Awesome..
Gym 4- Elesa
No.of Tries- 10+???
Pokemon used- Herdier, Roggenrola, Darumaka
Horrible. Just Horrible. I tried to use my Roggenrola to take down at least one of the Emolga, but they just keep using VOLT SWITCH! I dont want Roggenrola to faint because it also gets a lvl up and evolves, and if it faints and I lose the battle, it pretty tough, cause I miss Power Gem( I dunno why but I wanted it even if it sucked) and another lvl to evolve it.
Finally, I hit succes and killed an emolga which switched in with rock blast, then used Herdier and kept feeding it potions till it slammed Zebstrika( first weakened by Darumaka, who fainted afterwards) and then somehow managed to kick emolga in the end.
Gym 5- Clay
No.of tries-3
Pokemon used- Scraggy( KO'd all three pokemon), Dewott and Darumaka were on the bench
Ok the first two times I restarted because I wanted my Scraggy to not hurt itself in confusion. :P But anyways, the third time was awesome, first I KO'd Krokorok, then Moxie comes into affect, then KO'd Palpitoad with Brick Beak again, and another Moxie, then its out of confusion, Excadrill uses hone claws and Scraggy KO's Excadrill in one hit. A clean sweep I say!
Gym 6- Skyla
No.of tries- 1
Pokemon used- Joltik, Darmanitan(was on the bench actually. :O) and Boldore.
Ok so Joltik KO'd Swoobat and then Swana with Electro ball. Oh, and then Boldore just finished off Unfezant with one Rock Blast.
Gym 7- eh, what was his name again?
Pokemon used- Scraggy sweeped them anyways, Boldore and Darmanitan on bench.
No.of tries- 3
Kinda the same thing with Gym 5. Killed Vanillish but then Beartic comes in and uses swaggers, which confuses Scraggy and I get annoyed and restart. Anyways, on my third try, kinda the same thing, Scraggy sweeped his whole team. xD
Gym 8- Drayden
No.of tries- 1
Easy peasy. Scrafty to try and get in some hits, Darmanitan to spam Flare Blitz and suicide, and Ferrothorn(Yes, its first gym appearance. Somehow I never felt it was got against the ice gym when I had pokemon like Darmanitan and Boldore). Ferrothorn basically used ingrain, curse and allowed Haxorus to just use dragon claw and commit suicide. xD