I've seen both of his games so far that he's pitched in. Basically, his stuff looks great so far...to the surprise of any Ranger fans who collectively thought the guy was going to be a bust. I think he'll continue pitching well in the near future.
That being said, I don't think he'll hold up all year. Once the Texas heat hits, I think he'll break down. He hasn't pitched over 40 innings in the Majors since 2002, which I guess could be viewed as a good thing...but I see it more as a bad thing. I really don't think he'll hold up, but if you're looking for a short term fix then I guess he could work. Still though, watch the matchups...especially in Arlington.