It seems as if you have made your decision based on your first and most recent post, but the subject of the thread that you started is "What's y'all opinion on these boxes." So...since you asked, I will offer mine.
I have diligently read all threads about the Harbor Freight 44 and side boxes, even went there on multiple occasions to check them out, but recently received the free SnapOn catalog in the mail at my request. I have spent a bit of time replacing my Craftsman USA socketry and other hard line with SnapOn because I believe in US made and SnapOn quality. I probably will never break a Craftsman socket with what I do, but for ME, it is the principle of the replacement. My tools, my choice. Again, my opinion and you asked.
As for the box, I have had an internal struggle with this one. I wanted to pull the trigger on the HF 44 with side boxes this weekend during their sale, but I didn't. As a non-professional(for the purposes of this discussion), I have a very hard time stomaching the price of SnapOn boxes, although I want one based on my ideals. I can afford both, but the price difference is tough to justify, so I acknowledge your dilemma.
For me, I have made the decision to replace all my tools with SnapOn first, where they can live in my 2005 26" Home Depot Canadian-made upper and lower. Once I have the tools that I want, even stuffed to the gills for a bit, then, and only then, will I consider throwing down the cash for a SnapOn chest. If I can't stuff what I have with what I want until then, then maybe I'll get a HF, but it will be temporary until I am complete buying tools and can shift fires to the box. But that is me and my needs. Yours may differ- I am not a pro, but having handled Harbor Freight tools, US made Craftsman, I have made my choice. It is personal one, as I feel yours will be. If you have the cabbage, then I say go for the SnapOn. If not, then my opinion is that, like me, wait for your personal situation to tell you when the time is right, if ever.