Any difference in size between it and the black box?
Exactly the same...just forgot I had one in blue. If I made my favorite mod using that one first I would have learned I had more options on spacing of components. The new info will help me remake a few of the black box ones. What I really need, and I've had a hard time finding it, is a small 3a switch. I like the horn style, but all the ones I've found are too long. That's the only component I'd change....the box is perfect for me.
I've gone "minimal" on a couple of 3.7v boxes I've been working on. I do love VV because it opens up different options, but I can't get away from a good 3.7v. I replaced the copper wire with pure silver and it seems to make a big difference in performance. Nothing scientific; just an observation.