I know this is an old thread, but it pops up everytime you search for these products so I figured I would add my experience.

I tried both, both worked to soften my stool without making it too large (a concern I had with fiber). But I found that Miralax made my stool very messy and harder to clean, which caused more pain and irritation. With the Docusate, the stool is the same constancy coming out, but when I wipe it seems a bit watery. But it only takes 2-3 wipes with babywipes to get it clean. I've been taking 2 100mg capsules per day and haven't changed anything else, still eat lots of meat and not enough veggies lol.