Actually, it really didn't matter either way. This one just looks better IMO. The primary goal was to have two 2-cell banks (which are completely independent) in a smallish package.
The first one was about $30, but I got a lot of extra parts, so it's hard to tell. The only thing I had to buy on the second one was the case ($7 shipped) and a switch ($3 IIRC); everything else was stuff I had.