Fit has the best space and most...errr...utilitarian? interior. My Dad has a 2010 and it's been used like a truck most of the time (dead deer, tools, mulch, trapping supplies, fishing stuff, ect) and it's been problem free in 40,000 miles. It's a comfortable, easy to drive little thing that has pulled around 38MPG lifetime on the highway for him. I'd gladly drive one of the little tricked out sport version ones. It's one of the only cars Honda has out right now I find remotely appealing. It's not bristling with power, but it felt plenty quick for it's size and was able to get out of it's own way.
The sonic has the best power of the bunch and likely best economy in the 1.4T trim. I haven't drove one, but it's supposed to be a punchy, fun to drive little car. Economy is supposed to be easily 40+ on the highway. I've looked at them in the dealer and the back seat is nothing but a place to toss things. It's horribly small. I'm not sure if my 4 year old could even fit back there if I was driving.
No real comments on the Fiesta/2. Both of them are bit...buggy looking to me. Although the sonic isn't exactly much to look at either.
You should give the Kia Rio a shot too...decent