I am thinking what improvement I can offer over the bigger brands to make it a viable business. It's not going to work if I just make similar product with only very minor differences e.g. a few mm in dimensions....Haven't seen the XSPC one before, most likely discontinued now?
My preference is the rectangular-shape like the XPSC one, so other example of such shape is the Iceman res for the Meshilicious and Alphacool DDC 1U res. The Alphacool is great with so many ports for flexibility, but as we all know it leaks. I feel the Iceman is almost as good as we can get - maybe find some way to slim it down and/or shrink the res part to reduce the volume further?