My take, I haven't gotten to play my first game yet, but we should keep in contact? Since we'd be around the same point of learning eh.
My takes why I play Iyanden:
-I played Ulthwe, USF, and Biel tann, experienced and looking for change.
-Iyanden is very unique, it catches peoples attention, with its models and including color scheme.
-Iyanden has a really low model count, which means easier painting, without that much hassle.
-This army is very durable, and can pack some serious power.
though This is not your everyday begginers army. If you are pretty much looking forward to Constant winning, this may not be the force, as you will actually need to do some serious planning on this army.
You are:
-Going to be outnumbered
-Mass and CC could be your weakness in some cases.
-Possibly outgunned
Though it is not to say that Iyanden is extremely hard, I feel that takes time to get use to and understanding. It pretty much could act as a Vanilla/Standard Eldar force with some inverted Force Organization charts.
If you are willing to go iyanden be prepared for:
-Heavy costs, if you buy retail, then I pray for your soul. (I happen to get my army from discounts and trades)
-Weapon mounting conversions, I'd say that if you truely play a real Iyanden force, you better be prepared for flexibility which means magneted weapons all around for your force.
I.E. Starcannon wraithlords are good against SM, but against Nids, you'd need that flexibility.
-Lose, the harsh reality.
Iyanden can go few ways:
Untraditional: Minimized wraithguard size, maximizing Wraithlord fielding.
Then spending points heavy in areas of: Elite, Fast attack, and heavy support.
Traditional: Wraithguard/Wriathlord Heavy
Mech: Utilizing transports to take you to the heart of the enemy, though you are extremely low in numbers.
Footslog: Your whole force is ground, your force will take a long time to get up into to the heat of battle, but you rely on numbers and armour.
Hybrids: Combination of both, utilizing tactical ability with speed while your other force finally arrives to deliver the heavy blows.