Wait until you play Eldar....
I haven't lost a game to Eldar yet. 6-0. I don't have anyone that plays seer council, but I've got a guy that is going to run Wave Serpent spam against me soon.
It is probably an Apples to Oranges comparison. 1 of the Tau players is the closest to a power gamer that exists in my local meta (prefers 3 riptides, 3 Broadsides, 2 Skyrays, and lots of suites), and the other two guys who play Tau sometimes play net lists, but each only have 1 Riptide. Meanwhile the only Eldar player that I see regularly is a very "fluffy" player.
ETA: I tend to fluff up my lists when I face him while staying competitive. I haven't been doing a very good job of that (because I'm 6-0), but we've played a number of close games.
tag8833, interested to hear what your optimised beat Tau 15% of the time looks like?
When I play against trip-tides tau, I usually run dual flyrant + venom in a box + 3 Mawloc. Something like this:
Tyrant (Wings, 2 TL Devourers, Hive Commander)
Tyrant (Wings, 2 TL Devourers)
Venom -> goes in bastion
Zoey
10 HGaunts
10 Tgaunts (spinefist)
25 TGaunts (10 spinefist, 15 Devourer) -> Outflanking, then kill as many broadsides / suites as they can then tarpit a riptide / broadside over an objective if possible. This units has as many riptide kills as any unit in my list.
20 Gargoyles -> usually exist to bubblewrap and then eat overwatch if I want to charge with a flyrant. Sometimes they tarpit a riptide that gets out of range of combined overwatch.
Mawloc -> Winning and losing usually comes down to deep strike scatters.
Mawloc
Mawloc
Living Artillery -> Crones work just as well (0W-3L-2D record), except my opponent feels the need to list tailor when I run them, and thus is unhappy when I don't let him, so I usually keep the Exocrine instead.
3 Warriors(2 devourers, BS) -> on top of bastion
3 Biovores -> Snipe out the marker lights.
Exocrine -> Kills broadside if it gets the chance.
Bastion + Comms.
Running that list, I can sometimes beat Tau. 15% or so. But it usually requires luck. Once a Mawloc arrived, Killed one broadside, and the other 2 ran off the table. That game went well for me, but ended in a draw. I need good Mawloc deep strikes to eliminate most of the marker lights, and broadsides. Another helpful thing is Onslaught so that I can onslaught a tyrant to kill a skyray. It is a terrible trade, because that flyrant is almost always dead the next turn, but if I can pull it off when the skyray is still full of missiles, it is worth it.
I know the list looks really light on synapse, and it is. But it is also really close to being tabled, and rarely do I lose my synapse without getting tabled. I used to drop the gargs for a Trygon Prime, but he figured out to kill the Trygon prime first, and started killing it with interceptor before it could even shoot.
To give you an idea of the Tau (Farsight) list I'm usually playing against, here is his standard TAC list.
Commander (2 missile pods, Talisman of Arthas Moloch (4 dice DTW), Target Lock) + 2 Marker lights
Riptide (Interceptor, Skyfire, Eathcaster Pilot Array (reroll Nova), HBC)
Riptide (Interceptor, FNP, HBC)
Riptide (Interceptor, FNP, IA)
3 Crisis Suites (2 Missile pods, Target Lock) + 4 Marker Lights -> Joined to commander
3 Crisis Suites (2 Plasma, Target Lock) -> Deep striking
3 Crisis Suites (2 Flamers, Fleet + Hit and Run) -> Deep striking, or walking on sometimes because I'm outflanking gaunts
2 Crisis Suites (2 Flamers) -> Deep striking, or walking on sometimes because I'm outflanking gaunts
Skyray
Skyray
3 Broadsides(HYMP, 1 Skyfire, 2 Target Locks)
Sometimes he drops a riptide and some suites to bring in buffmander + Kroot. He tends to add buffmander to his Crisis suites, so it doesn't worry me as much as if he attached him to the broadsides.
Anyways, I'm not saying my list is perfectly optimized to beat tau. But I will say that if I run that list against non-Tau opponents they tend to get very upset, and concede fairly early. I did run this list against IG mech and lose, but I failed all of my grounding checks, and did a bad job deploying.