b - you're focusing too much on sets that fit in your pocket (which makes them less useful as general tools), unless there is some other consideration you haven't mentioned. You probably won't use a 1.5mm key, while you sometimes will use an 8mm key. However, the 8mm key in the topeak tool is likely too wimpy to use in practice.
Is $8 too much for a proper set?
http://www.harborfreight.com/cpi/cta...emnumber=65425