Same here, the critics seem to be divided 50 / 50. Still can't wait to see it, although I wish it gave more insight into the Bre-X mining scandal.
I read this on Indiewire:
Directed without distinction by Stephen Gaghan, the film unfolds like a chintzy ripoff of David O. Russell ripping off Martin Scorsese ripping off real life.
While Variety is more enthusiastic:
Proudly sporting a pot belly, snaggled teeth, and receding combover (though any normal person with either would go out of his way to hide them), McConaughey turns in a gonzo performance as a gold prospector named Kenny Wells, who improbably strikes it rich after acting on a hunch that takes him deep in the jungles of Indonesia, only to lose track of the claim as smarter men than he try to get in on the deal.