I don't know how common the failures are on these but I have gone through 2 of them in pretty short order. I'm not going to spend $20 on another one when I've not been happy with them.
The issues I have are :

1. Hard to open and close
2. "Sticky" to put things in and get out
3. Tear far too easily
4. Did I mention expensive?
5. Loss of fine grained touch screen sensitivity

This was the solution I came up with. An extra benefit of this is I can store maps in additional ziplocs and just move the internal strip to swap out map sets. Super cheap and works just as well, actually, better.

I hope this is useful to some folks or gives you ideas of your own. Enjoy.

YouTube Video of Ortlieb Map Case Replacement

Clever solution to an annoying problem. Even if I don't use the Ortlieb bag (I have a Jandd) it's fun to see someone else's elegant ideas.

Wouldn't those magnets be a potential issue for any credit cards you might want to put in your handlebar bag? He mentioned they were rare earth, which are pretty strong. Strong magnetic fields are unfriendly to the magnetic strips on credit cards, and the internal zip pocket inside the bag is right under where he has the magnets set up. And even if the position inside the bag is far enough away to not be an issue, you'd have to be careful whenever you take your wallet out of the bag, just passing it close to those magnets could wipe your cards. Or am I way overthinking this?

I have had mine for years and never had a problem. I wil admit it is a bit hard to open and close but then again, you could submerse it in water and everything would be bone dry.

When I bought Ortlieb rear panniers of the plastic hooks didn't fit that well across the rack stays. Instructions didn't mention it but it was quite easy to flip it over, using a Torx wrench. Kudos to Ortlieb for using Torx bolts instead of delicate tiny allen.

The magnets are way too weak for the credit card wipe issue. I used to work dealing with credit cards and our in-house ski resort cards. We did some tests on what it would take to mess up a gift card and we couldn't do it with any of the magnets we could get our hands on. The reality is its pretty hard to do. Does it happen? Sure.

Pipe cleaners and a plastic literature sleeve. Done.

Nicely done and very clever. Even though I do not have an Ortlieb bag your ideas will come in handy.