Necrons
The dreaded broken list. Necrons are fast. Necrons are resilient. Necrons hit hard. Necrons make Eldar cry. Firstly, all Necron ships have great armor at 6+. Secondly, they get a save vs damage depending on the ship class: Escorts get a 6+, Cruisers get a 5+, and Battleships get a 4+. When under the "Brace for Impact" special order ALL Necron ships improve their save to 2+, but lower their armor to 4+, and finally, Necron ships repair critical damage on a roll of 4+ instead of the normal 6+. The Necron weapon battery does not suffer the normal column shift for eldar holofields or shadowfields, and treats ALL targets as closing. Necrons have a "Star Pulse Generator" which grants an automatic roll to hit against all ships in range (one roll each), which ignores Holofields. The Necron lance equivalent ignores shields on a roll to hit of 6, again Holofields cannot save against this. Necrons love to get up close and personal, where their "Portals" give them extra hit & run attacks. While they don't get bonuses to these rolls per se, the ability to make multiple H&R's per capital ship, and ignore most of the restrictions pertaining to such make this much more of an asset than normal. Necrons can close very fast; The "All Ahead Full" special order grants them an addition 1D6x10 cm's of additional movement instead of the normal 4d6, and they can turn once for every 20cm travelled unlike other races which cannot turn at all. The firepower and strength of Necron weapon systems are affected by special orders as normal, as are their turret values, making lances very valuable against the tin tide. Causing Necron ships to 'Brace for Impact' by firing fusillades of lance fire is also helpful as they cannot 'All Ahead Full' while braced. Also, since Necrons don't have shields to absorb incoming fire this means that there are no blast markers placed by the lances, leaving weapon batteries unaffected while firing second. The Necron fleet has it's own victory point table which is very harsh - any cpatal ship which is destroyed but not left as a drifting hulk (meaning it exploded or is otherwise not on the field at the end of the match) is worth 200%, and a drifting hulk (destroyed but still on the field) is 300%. Also, for campaign play, Necrons are charged double the amount of resources to effect repairs. I think the drawbacks are fairly balanced against the advantages, especially in campaign play, as Necrons are unable to upgrade at all while their opponents will presumably be getting more powerful and efficient ships.