On comparing the two, this article in today’s Times sums up my thoughts and feelings pretty well. In particular, it gives a good appraisal the weaknesses of No Country for Old Men:
But I simply don’t know what the last half hour of this Oscar-winner means. It’s a bloke’s film in the crudest sense of the word. The desert landscapes are framed like paintings, and the plot hardly breaks sweat. But for the life of me I could not picklock a meaning from the last chaotic, whimsical, in truth, desperately-looking-for-an-ending, reel. It creaks with significance, but I left the cinema not entirely convinced that the glittering plaudits it has won are entirely deserved.
There Will Be Blood, on the other hand, while leaving you with a lot to think about and many complexities to untangle, particularly Daniel Day-Lewis’s character, gives you some clear and solid themes to chew on, rather than leaving you scratching your head as you try and work out what it was even about, let alone what it might have been trying to communicate.