Well, on the tyranid front, at Adepticon we had a 12 man 1500 point BFG tournament (about average for the event) with this fleet breakdown.
2 Tyranid, 2 Chaos, 2 Space Marines, 1 Tau, 1 Necron, 1 CWE, 1 Corsair Eldar, 1 Ork, 1 Dark Eldar.
One of the Tyranid fleets had 2 of the 14/6 monstrosities. That fleet won best general and if it had been a little better painted (one of the judges was a lot harsher than the other and gave the fleet a 0 for the paint score based on the criteria involved) would have won overall by one point. The final game table was against the Tau fleet and the Tau player could do practically nothing to the hive ships (I'm 99% sure he was using counts as rules for his FW ships and had 3 explorers).
The other Tyranid player was unupgraded and ended up in 8th place and in 9th place on the battle scores.
There were actually quite a few complaints about the hive ships from the first player. So much so that I'm considering a limitation on the number of upgrades to 3 per ship instead of 3 types per ship for 2011.