I don't want to give too strong an opinion since I don't know the specifics of the cars or your situation, but if you could get the price close I'd be tempted to go with the 2010 with the least miles (note though, I don't think dealer sold cars are necessarily more reliable than private, but perhaps it's more of a known quantity). Honda Fits in some areas seem to keep their resale value relatively well, so you may get back some of the premium you paid if/when you sell. I think it will all depend on your personal evaluation of the three cars and what makes most sense for you.
For context, we have a 2009 Honda Fit sport (it's the second Honda Fit we've had), and think it's a great car
Our car was bought used from a dealership at about 40,000 miles, is approaching about 85,000 miles now (mainly highway while we've owned) and we've had no major issues or expenses besides wear and tear parts (breaks, tires, wipers, lights), and normal maintenance. I wouldn't worry about putting 15k miles a year on it at this point, though now that I'm older and wiser I might question why I can't figure out a way to drive less :)
Some randoms thoughts on the pros/cons of the Sports model:
While it's badged as a sports model, the decision is really base vs slightly fancier, since there are only two trim levels. I'm sure the base would work fine and is still a pretty luxurious car, but the up model is nice to have for the cruise control, power doors and windows, and remote entry.
Our car can also play MP3s directly from an ipod/iphone and also charge a phone from USB, I don't know if the base can do that, and it's not a deal breaker, but it is nice on road trips.
If you are looking at automatics, the paddle shifters that come with the sports model do make the automatic transmission a bit more tolerable, especially on roads with a lot of elevation changes or sudden merges. The better solution is probably to get a manual if you can, I think it is a better fit for the car (though with the limited availability, we had to go with automatic when buying used).
I'll admit, I think the spoiler and body skirt they add on the sports model make it look a little nicer. Maybe in theory they make it a little more fuel efficient (maybe), and maybe improve performance (probably not).
BUT they have practical downsides: the spoiler makes it hard to find a trunk mounted bike rack that will fit. We went with a hitch mounted bike rack for this reason. The skirt also lowers your clearance a bit, so it's easier to catch curbs, makes speed bumps more of a pain, and I guess would make it harder to go offroading if you wanted to do that.
The skirt also makes it slightly hard to find where you have to jack the car the first time you need to change a flat, especially if you have to do it confused and in the dark... fun times...
The sport model also comes with slightly larger (or wider?) tires I think. Again, they make the car look nicer I suppose, and less shopping/go cart like. They might make the car handle better or be more responsive in turns, but I think it'd be a moot point if you are looking at such a tall car anyways. If/when you have to get new tires, they are also more expensive and harder to find than the tires for the base model.. again this might just be our experience.
Hope some of that helps. We are
quite happy with the Fit in the end
