I've played two games at 1000 point consisting of:
1 x Flyrant TL Dev x2
1 x Zoe
1 x Venom
1 x Venom
1 x Exocrine
The first game was against Grey Knights, and it was really important to realise that although you don't take IB tests when in close combat you do take losing combat leadership tests when out of Synapse range resulting in 30 termigants being wiped out by a Vindicare assassin in close combat by sweeping advance. Technically I won the game on objectives, but actually there's little a Tyranid player can do against Paladins - shoot them and they have 2+ armour saves, close conbat them and they force MCs to death and destroy the little critters.
The second game was against Dark Angels (nothing special) except he took two libbys and rolled invisibility for them both then never cast it. However, I had the first turn and my Hormagaunts did the full 15 inches. He didn't fire at them as he was trying to bring down my Flyrant (which he did and then took it down to 1 wound), which meant my Hormagaunts then proceeded to eat through 1 x ten man tac squad, 3 x bikes, 3 x scouts, finish off other tac squad, while the flyrant shot the libby and finished off the devastor squad with the skyfire missile he was with. His flank collapsed and then I piled through to the other flank.
In both game the Tervigon did nothing as it was babysitting an objective. Now I realise that I put termagants on an objective and make them go to ground.
Important lessons were - I thought I had enough Synapse - no I didn't. I think a squad of warriors is an essential troop choice to hold the back line.
The Exocrine is great as our only AP2 shooter.
Venomthropes are a mist. Yes Tau will destroy them and or take the cover away from other creatures, but not a lot that can be done about that except shoot the marker light drones out with the Flyrant!!
Need a second flying MC at more 1000 points. Probably take the Harpy as it is our only main anti flyer.
If you're going to go with Hormagaunts take 30 of them - don't go half measures. They can do MEQ in close combat with that number, but pretty useless against TEQ (especially TEQs with two wounds).
I wouldn't count this as a great success as the person I was playing was fairly green, deployed too close to me (allowing a hormagaunt turn 2 charge) and apart from focusing fire on the Flyrant on turn 1 (which would have really done my synapse in as it was holding the hormagaunts, venomthrope and exocrine in the attack) he never really focussed on any particular model and kept switching target priorities. Also there was no real dedicated anti flyer apart from one missile launcher in the second game.
If you are going "fast in your face" route, then I might well drop the Tervigon and take 30 Gargoyles. These also have the potential to get into combat turn 2 with a 12 inch move + run + 12 inch move, shoot fleshborers then charge. While blinded venom is a bit crap (especially given the description "how dangerous gargoyles can be .. blinded and debilitated", as you have to take a blind test for every hit, you can be fairly certain they will blind them.
At the very least the Gargoyles should tie up a squad to "relieve" you of a couple of turns of being shot at while the slower creatures lumber along.