No experience with the straw but I do use the Frontier Pro and I haven't been sick since using it. It's light enough and it's adaptable to many application (i.e. plastic bottle, gravity system, etc.)
Only complaint I have is that it is limited to filter only 50 gallons - compared to the Sawyer Squeeze and others. Also, both the straw and the pro are NOT for purification, they are just filters.
Here's an article discussing the differences between the two. I hope this helps.