When I was asking the same question a while back the majority of people said go for it. If the horse has been blind in one eye for a long time then she will have adapted and it will not cause her a lot of issues. You also want to know if she was blinded by an accident or if there is any underlying medical condition.
You need to make sure that you warn her verbally if you approach her from the blind side and just remember that she has areas where you could surprise her.
It certainly isn't like buying a car that can only turn one way, and she can certainly be more than a pasture pet. As ever the best thing to do is to go and see her, ride her, and work with her on the ground, if everything else is perfect then go for it