There are several reasons I want to use him:
1. He looks cool
2. He's the best Haemonculus there is
3. He's got some interesting rules and wargear (I love the concept of Clone Fields from both a gaming and modelling point of view)
Now whilst I consider myself competitive (any gamer should do really) I'm not a WAAC player. So that gives me the chance to come up with lists that break the mold and go against conventional wisdom. I will more likely than not play this force at future Throne of Skulls tournaments etc. but I'm under no illusions I'll win, so that takes some pressure off for sure!! I tend to find more fun players in the middle/lower ranks anyway!
So, if I am to build an army around Urien, I need to consider both him as well as his rules. Now, he is a Haemonculus, so he starts with a Pain Token. He also makes Wracks troops (so I don't have to include other Haemo's if I don't want to) can supercharge a unit of Grotesques and also dishes out D3 Pain Tokens to Wrack and/or Grotesque units in the army. He also uses a Clone Field as his primary defense - no Shadow Field here.
So with that in mind, what should I consider?
a. Use Wracks as troops
b. Use Super Grotesques
c. Figure out how to best use the Clone Field to keep him alive
The obvious choice is to pop him with the Grotesques, as they start with a Pain Token, so does Urien + he could give them another for the awesome FNP/Furious Charge/Fearless combo. However Grotesques, at least how I see them being used, are a small unit in a Raider - as such, there is a possibility of him getting attacked more than I'd like. So the alternative I have been considering is to put Urien with a different group for protection... namely Bloodbrides. Why Bloodbrides? Well, they can pack more shardnets than wyches (3 of them in a 9girl unit) and this makes them effective at lowering the number of incoming attacks. With effective placement, I can limit the number of attacks coming in on Urien and with his Clone Field I can potentially keep him alive longer. It would also mean the Bloodbrides start with FNP and fit nicely, with Urien, into a Raider. Lovely. The only real downside is Urien isn't Fleet, so I will have to take that into consideration.
What about the Grotesques though? Well I could still have the same combo by giving them a normal Haemonculus, so that is a consideration. Grotesques have a number of issues however, so I do need to consider those carefully before I commit any thought to that. After all, defensive options for normal Haemonculi are pretty much non-existent and you lose the IC... then you lose the unit. Urien seems to get around that with decent toughness and regeneration, but I still worry for his safety in a small unit.
As for Wracks, I can see these working either as small 5man+venom squads (Liquifier Gun) or larger squads in a raider. To a degree it'll depend on what I decide to do with the Grotesques and how all the points hang together.