So you guys snagged Jordan Black from the Chiefs more than willing hands. For a little primer, check out this Jordan Black thread from my favorite Chiefs message board.
Jordan Black was not that successful or very popular in Kansas City. He isn't especially good but he can play basically any position on the offensive line, save center. But you get what you pay for. You guys didn't over pay for Black and considering your current state of the offensive line, I would consider any decent player (which Black is) coming in would create some healthy competition.
This isn't a blockbuster signing by any means. I'm sure the Texans knew what they were getting in Black and for the time being, he seems to be an improvement over what you have now so you can't fault the Texans for signing him.