which army to choose?

[Pater Sin]

I'm not sure which direction to go next, I've got CSM with deamon allies, a small Tau force (about 1500 points) and a slowly expanding Dark eldar army. For my next army I was thinking Necrons or Tyranids, If can get a bit of advice about strengths and weaknesses and such it would be apreciated.

[Jax]

Hey mate, I suspect that given your current army selections you're not adverse to some of the harder to use armies? The Tyranids will be an enormous departure from your current armies, yet they have a huge number of draw backs - such as that in a competitive sense they are a mono - build army; which isn't a good thing. The Necron's are currently one of the better armies rolling around in 6th edition and have some really nice models to boot, you really need to look at the codex and get a feel for the force though before you commit because they are terrible in combat except for a few select units. It's really down to personal taste and what you want; I think that Tyranids are an interesting army and there isn't anything that plays like them in 40k (no vehicles!) and there really is nothing cooler then swarming a board with monstrous creatures. If you're on the fence, we do provide a break - down and analysis of the Tyranids here (http://imperatorguides.blogspot.com.au/2013/02/tyranid-tactica-6th-edition.html) on our site. I can't help you too much personally with the Necron's, but there are many people on this forum who will be more then happy to help you with Necron's if you're inclined to go that way.
As always, check out the models first and try and visualize how you would like them to look and whether thats a road you'd like to go down.

[Renegade]

My opinion from playing against Tyranids, is that the more diverse you are the better. They take a while to master but are a real pain when played well.
Like Eldar, each unit has particular strengths that one has to think about. A good player will find these and target them to break the links in the chain, so make sure the chain is a strong one, which should not be to difficult.

I have use and played against Necrons a lot, and found that they are very resilient. Quite a forgiving army in the hands of someone who has experience of the game but new to the army. The only bugbear is that the good stuff costs a lot of points, so best off getting the codex first and deciding what you want to take.

You'll have a learning curve with nids, while crons should be fairly simple to pick up and play.

[Lost Vyper]

Eldar army would be a great asset to your Tau or Dark Eldar army as allies...or vice versa

[Kaiserdean]

From a painting perspective, Necrons are the way to go.

You can do it quick and easy with a can of silver primer, or go all out and really paint some flashy bits on those guys. Bugs are easy to paint too but I love the space robots.

From a gaming perspective, the Necron flying list is all the rage. Bugs aren't as competitive on the tourney circuit, but still have a few winning players.

From a dollars and cents perspective, they both seem to need about the same about of models (depending on your build of course). Necrons, of course, are better allies for your other armies too as bugs can't ally.

[Pater Sin]

While I apreciate the advice Vyper, I plan to leave Eldar for my brother, as it is I think I'm going to go for crons just because they look easier to paint and in the long run I don't want to get half way through and give up like I did when i had orks.

[Demonus]

Crons baby. Army Painter silver primer, some black wash, high light colors of your choice and some black for the weapons and you are golden. LOTS of competitive lists, not just flier spam. I myself, use 2-3 fliers tops, mix in a small wraith squad, maybe some scarabs for armor munching, bunch of gauss and tesla troops, and a goat boat (ann barge) or 2 for good measure. Tons of fun.

Plus you can have some great fluff battles vs your brother's Eldar.