Tough question. It's all a toss up!
The closer you get to paradise the more places there are to get fills right on the water, and usually cheaper than the US, or at least NJ, where I am now.
Also, someone on Cruiser Forum mentioned that at least in the Caribbean, more and more of the islands, up to 1/3 now, are restricting private diving anyway.
On the other hand, the compressor is great to have if you want to hit more remote spots.
Guess I could store it in one of the lazarettes until I get to those locations. But as I said, very heavy. It would have to be lowered in there on kind of an angle, and sure won't be easy to lift it back out.
I'm on a cat, so weight is an issue too. Foredeck, probably not a good idea anyway, but it would interfere with the genoa...and block the view from my master stateroom. In a case behind the mast (best spot as far as space and weight distribution goes) but it would restrict my vision from the helm...especially when docking/motoring in high traffic areas.
Pretty much leaves me with cockpit or lazarrette. Could always leave it in the cockpit and make a cover with a cushion for it, so it's least kind of usable, but still going to take up a lot of space. Either going to block the door from fully opening or going to block one of the lockers.
Maybe go with a hookah for those really remote spots? I'm not a fan, but cheap, small, and lightweight?
Or another option, although probably not a great idea, could be removing the components from the frame, and building a custom frame to try to get it into a smaller package. Or maybe even mounting them directly to the boat inside of one of the lockers?