Honestly if you don't like the DLC and don't think it is worth the cost, don't buy it.

I've bought some DLC (all 3 song packs for Guitar Hero 2 and the DLC for Crackdown) and I've enjoyed it.  For me, it was worth the money, and I enjoy what I got.  I can understand if you don't think it is worth it, but no one is forcing you to buy it.

Up Yer Arsenal is a better game, but Deadlocked has more online features.

If your going strictly based on Online, Deadlocked.