Tim, I have an Asian bandsaw, but would jump at a chance of buying a powered hacksaw if I had the money for it:
The bandsaw is pretty difficult to get to cut squarely; horizontally it's still ok, but vertical cutting is difficult to get square. Even in different materials, it is inclined to cut at different angles. I use mine for pretty darn any metal that needs to be cut - silver steel, mild steel, brass, aluminium and cast iron, as well as wood & plastic on occasion. Normally, this would necessitate a blade-change for different metals and thicknesses of cut to get an appropriate tooth spacing, but changing the blade on mine is a serious PITA, so I use one blade for all jobs; makes cutting thick pieces slow because the blade is too fine, and when cutting thin pieces I have to manually hold it back to prevent it stalling (or stripping teeth from the blade), as the teeth are too course.
From what I've seen, changing blades on the powered hacksaws is much easier, and by the nature of their design they are much easier to set up to cut square - that's why I would prefer the powered hacksaw.
One advantage of some models of bandsaw is that they can take a mounted table in vertical operation that you can use to free-hand cut. I've never seen a feature like this on a powered hacksaw.
So in my opinion, if you've got the pennies, go for the hacksaw; they are normally more expensive - that's why I ended up with a bandsaw.
Make no mistake though, a bandsaw still beats the heck out of sawing a thick bit of barstock manually!
Cheers, Arnold