It all works out the same in the end really. All the time he's spending modeling, tweaking, redesigning, and repeating, you will spend the same amount of time applying spot putty/bondo/abs slurry and sanding and sanding and sanding and (you get the drift). A common occurrence I've noticed (In general, not you specifically. Just seems like a good time to bring it up) is that 3D printing is not magic and a lot of time goes into modeling and tweaking designs so it's not just click and print all the time. In my Nomad Jr. case I'm sure I have over 40 hours invested just in modeling and tweaking and I still have to fix the top part some.
It all depends on what you enjoy though. I'd rather put 120 over hours of work into a 3D printed case than put even 10 hours into a frankencase mod, just because I enjoy CAD more. Someone who has more "hands on" experience than computer modeling probably feels the exact opposite way.
Yeah I agree a lot with Wallydawg. I enjoy 3D modeling much more so far because it allows me to have a theoretically perfect case and I spent hours and hours of my last portable trying to get it perfect and never reaching the level I wanted.