I don't have a lot of BFG experience under my belt yet, but I hear a lot of disagreement about whether Necrons are brokenly overpowered or not. I'm curious how much of that's an actual disagrement, and how much it hinges on the different ways BFG is played.
Now, I've found a lot of groups just play Necrons wrong. If you give them a regular brace save in addition to their special save (i.e. to hurt a braced tombship you have to get a hit, then have them fail their 2+ save, and then they also have to fail a 4+ brace save), allow their save against hit and run attacks(without bracing), or allow their save against boarding actions, then they get overpowered fast. Others forget that locking on actually shuts down some necron weapon systems. But those can be corrected with a look at the rules and even older FAQs out there.
Aside from that, there are groups playing with the 2010FAQ/Update and those that aren't. That didn't affect Necrons so much. But it did affect the other fleets in a number of ways that I think generally make them better against necrons. Some fleets got all sorts of new toys and fleetlists, and turret suppression stands out as being no help to necrons at all, but it makes other fleets better able to hurt necron ships.
Another common difference is the sort of scenarios you play. There are the origional scenarios. However most of them don't have turn limits and either don't use VPs at all or don't do so in a meaningful manner. So the necron's VP weakness is effectively eliminated.
Then there are tournament type scenarios, which always have turn limits and generally use VPs in a meaningful manner.
I notice that Necrons don't seem so popular in tournaments that use the 2010Update and "tournament" scenarios. So I wonder if the community might actually be in agreement.
I.e. I'm thinking the situation might be:
Play necrons wrong and give 'em a bunch of extra saves and attacks? Waaaaay OP.
Play them with a fleetlist that doesn't feature many lance weapons? They'll seem OP to the noob with that list.
Play them under "old" rules found on GW website: Notably OP.
Play them under the 2010 update and old scenarios? Good, but not too OP
Play them under the 2010 update, with tournament type scenarios, and opponents that gave some thought to beating Necrons when they built their lists? Actually balanced if not a little more vulnerable to bad luck than a lot of fleets