Warhammer Community has posted the great army of the Fallen Angels by Eddie. We couldn't ignore them, since the new rules for them are now in stocks.
The article suggests two ways of using the Fallen units - close combat and shooting style. Since their rules are copied from the CSM's Chosen, they can easily perform both ways.
However, shooting unit looks more useful - they can infiltrate and shoot at their maximum effectiveness. This doesn't work with the close combat.
The Fallen have the yellow alignment with the Daemons - so why not taking such thematical Soulgrinder? This guy is great on his own and doesn't require any support.
If you are choosing between the Imperial and Renegade Knights - the latest is more preferable, due to the possibility to take 2 similar weapons.
It's great that the Fallen can also take loyal Spacemarines' vehicles as allies. This lets them compensate CSM's weaknesses - like lack of Anti-air and artillery.
Daemon prince is also a nice choice since he is a standalone unit and doesn't suffer if he has to be deployed in one army with the space marines. You can always put him in the reserve, or just set up somewhere aside.
Thematical Fallen army gives you really a lot of possibilities to use sets both from the Imperial and Chaos units.
Find out some tips in our blog:http://warzone40k.com/fallen-angels-army