I just ended a Super Rotations streak at
265 wins.
Team
My team is similar to what others have been using in that it uses a cleric to support a set-up sweeper while it does its job. My team is actually not all that far off from what Fatty mcfat cat used: same idea, just different Pokemon doing the same job.
Kangaskhan @ Kangaskhanite
Jolly
ivs: 31/31/31/31/31/31
evs: 4/252/0/0/0/252
stats: 181/147/100/54/100/156 --> 181/177/120/72/120/167
Scrappy -->
Parental Bond
Double-Edge
Earthquake
Sucker Punch
Power-Up Punch
Standard stuff. The trick is knowing when to go for the boosts and when to just attack right away. I would use Protect if I could fit it in, just to help guarantee successful Wish-passing, but the other moves are too important to drop (well, I guess Return could replace Double-Edge to eliminate recoil, but I like the power).
Sylveon @ Leftovers
Bold
ivs: 31/x/31/31/31/31
evs: 244/0/252/0/0/12
stats: 201/68/128/130/150/82
Pixilate
Hyper Voice
Heal Bell
Wish
Protect
The main perks gained from using Sylveon as my cleric are the Fighting coverage/resistance to support Kangaskhan and the raw power of Pixilate Hyper Voice (it hits pretty hard considering my nature/evs). Fairy is a great typing and Sylveon can sometimes just park itself in the active position and stall its way to victory.
Gengar @ Focus Sash
Timid
ivs: 31/x/31/31/31/31
evs: 4/0/0/252/0/252
stats: 136/63/80/182/95/178
Levitate
Shadow Ball
Thunderbolt
Psychic
Destiny Bond
A fast Destiny Bond is invaluable in Rotation battles. I've had many battles where the opponent will seemingly out-predict my moves/rotations to put me in a bad position; Destiny Bond helps greatly in these situations. Other than that, Gengar is a fast and decently powerful Pokemon that can chip away at the opponent to make things easier for my sweepers.
Aegislash @ Sitrus Berry
Adamant
ivs: 31/31/31/x/31/31
evs: 252/252/0/0/0/4
stats: 167/112/170/59/170/81
Stance Change
Iron Head
Shadow Sneak
King's Shield
Swords Dance
I just slapped this on as my fourth because I didn't know what would be best. In hindsight, Dragonite may have worked better, but Aegislash still worked ok. I would give it Leftovers if I could, but I can't, so Sitrus Berry will do. Sitrus Berry actually does ok with Aegislash's high defences in Shield forme, and when that's used up I can just turn to Sylveon's Wishes. This was originally a 3 attacks + Swords Dance set with Sacred Sword, but I found I wasn't using it enough. King's Shield works so much better and is especially useful for when I need to pass a Wish to it.
Threats
I never thought I would say this about any of my teams, but the Pokemon that have given me the most trouble are Fire-types, hence my comment above about using Dragonite instead of Aegislash. Having Earthquake on Kangaskhan helps, but other than that I lack a good option to deal with Fire heavy teams if I'm not set up. Such teams aren't exactly rare either, what with Black Belts/Battle Girls, Chefs, and Punk Guys/Punk Girls all using them as one of their specialist types. Even Legendary and Starter trainers have a good chance of generating multiple Fire-types in their teams.
Volcarona is the worst. I had many close battles with it and it ultimately caused my streak to end. Volcarona 4 is Bold 252 Def/252 HP so I can't just take it out in a turn with Double-Edge. Flame Body is very trolly to Mega Kangaskhan too. Sylveon can't stall it very well because Hyper Voice does nothing to it and it can just set up Quiver Dance. Gengar isn't strong enough and Destiny Bond is hard to pull off when it outspeeds you after 1 Quiver Dance. Aegislash is bad for obvious reasons (it can't even use King's Shield to weaken it since it's a Special Attacker). Unboosted Double-Edge + Sucker Punch kills it but with the randomness of rotations it isn't that simple.
Other annoyances include Infernape (Encore shuts down Sylveon, and it's fast and resists Sucker Punch, although Gengar can handle it well enough) and Darmanitan (ugh Scarf 252 Atk Sheer Force Flare Blitz).
How I lost
FUEW-WWWW-WWW6-QNKH
As mentioned above, Volcarona 4 got me. I made some dumb/unsafe plays that left me with just Sylveon and Aegislash to take it down. My only option was to try waste its Heat Wave PP before it gets too many Quiver Dances in, but it didn't work out. Funnily enough, I faced the exact same situation less than 10 battles before this one, and I used the same strategy against it, except that I was actually successful then!
I consider myself pretty lucky to get as far as I did considering the huge weakness my team had to a common type. I might give this another go with a different 4th Pokemon at some point.