There's nothing wrong with the products themselves... WDs problem was that they did not make buyers aware of the change they made to the product.
You wont have any issue buying the same brand / model...especially if you want to match your existing (working) drive. If you prefer to do a full replacement of all drives then no probs... just replace them both one at a time(dead one first) giving the system the chance to synch the data to the new drive before replacing the second one. Just make sure that you buy "CMR" drives and not "SMR".
Let me know if you have any questions....I'll try to answer them.

