Welcome to Librarium Online!
I have been doing USF and Khrone for a while now and wanted to switch over to a new Craftworld. Can you give details about the other craftworld, tatics that work, ones that dont and try to convince me into which would be the best to do. I kind of want one that is also good aginst tyranids and tau because my friends have them and I want to beat them :p
Biel-tan will give lots of aspect warriors but you'll almost always be outnumbered. Saim-hann if you like jetbikes/vypers and a really fast army. Alaitoc for snipers and scouts. Iyanden for rock hard troops and auto kill weapons.
Fluff answer: Iyanden, lots of wraithguard and wraithlord. Option to field 3 wraithlord as troops choices and i think their one of the better armies. The idea of a craftworld so desperate to defend themselves they use the spirits of the dead is just kind of intriguing.
Playble answer: Biel-tan, you can tailor the army to your needs, and its colorful so no dull paint jobs. Plus I love my banshee force, and Dark Reapers are troops!
40K-Beakies(9-14-4),Guard(4-7-2),Orks(34-12-11). FANTASY-Dwarves(15-6-7),Beasts (14-14-1), Skaven (17-17-10) DoC (6-1-2). CYGNAR (28-15-1)