I'd go with the 3. As ugly as Mazda made the current gen, they are still one of the best handling, best built small cars out there. The primary downsides are the appearance, a horrendous dealer network (many are just used car lot con artists), and some material quality issues.
My mom and sister both have 2.0L 3s, and my cousin used to have a 2.3 3. They are great driving little cars. Even the 2.0L is peppy, and the automatics have perfect, crisp shifting. They don't gear hunt a lot, or do lazy butter shifts. It is one of the quickest shifting, "tightest" automatics I have ever driven. Steering feel and other driving dynamics are also great for the class...it's a fun car to throw around, but also very forgiving in commuter situations. Basically it's very livable.
The problems...
- A/C is horrible - true of every 3 I have ever been in, including the three that were bought new in my family.
- Your dealer will most likely be horrible - maybe they couldn't iron out a deal with Mitsubishi or Suzuki or something, so they went Mazda. Mazda dealers tend to be awful. Do not use for service, do not buy warranties or service packages, do not go back. Get the car and run. If there is a warranty repair, you may be SOL. My mom thought she was being diligent when she took her 3 in for a power steering recall...it turned into a multiple visit nightmare when they fly by night crooks at two Mazda dealers botched the repair repeatedly.
- Materials - frayed seat belts and fabric on an '08, which is totally unacceptable. No vehicle my mom has owned before this has ever had messed up seat fabric or seat belts, let alone after 5 years. Other materials seem good, even above average, but Mazda fabrics/carpets are terrible. Actual assembly is good and tight - no rattles or squeaks.
Other than that, absolutely fantastic cars. Few mechanical issues, fun to drive, just an all around good design with a few hangups that are mostly not the car's fault. The terrible dealers are really the worst part of Mazda ownership.
For commuter car comparison, my dad has an '04 Civic Hybrid. If I had to drive that car everyday, I'd lose it. Horrible driving dynamics...I don't really know what driving a toaster would be like, but I imagine it would be like this car. The CVT is a lifeless, unreliable thing, sound system is unacceptable for a car built in the last 20 years, seats are rock hard (but look nice), fit and finish really isn't that great (probably not as good as the 3, just has better fabrics), and everything around the fantastic gas engine falls apart. The little 80 or 90 HP gas engine in that car has been absolutely flawless, needing literally nothing but oil changes and maybe an air filter or two...everything else has been flawed, sometimes severely (like $8K+ in warranty covered repairs severe).
