I've had a chance to drive this car (sGT w/out the tech package) enough now that I have some more well-defined feelings about it, so I thought I would update this thread with my opinions.
I LOVE the interior of this car. I liked the interior of my 2012 Focus Titanium, but this blows it away, and feels less cramped. I'm baffled by the few people who have said the interior looks cheap. Far from it. All of the car mag reviewers have gushed over the quality of the interior, although some have commented negatively on the screen sticking up from the dash. Personally, I like it. Everyone I've shown the car to has commented on how nice the interior is. The seats in the Mazda3 are more comfortable, and the extra leg room front and rear is appreciated, especially with my sciatica in my left leg.
As far as the exterior styling, I actually think I like the Focus hatchback better, especially with those wicked cool 18" 5-spook wheels from the Titanium Handling Package. I'm not terribly fond of the OEM 18" wheels on the 3, especially on the Soul Red car. They will be my winter wheels for sure. I like the exterior design of the hatchback 3, but not as much as the hatchback Focus. That may change once I get some nice black summer wheels. Also, when talking about sedans, I like the 3 better than the Focus sedan (which I find pretty boring to look at). I think I like the front end of the 3 better in either case, but I love the back half of the Focus hatch.
For the most part, I like the infotainment system, but the MyFordTouch system in my Focus was significantly better in almost all ways, except performance (it was a bit slow). I've gotten more used to using the dial/joystick, although I still need to get comfortable with it so I don't have to take my eyes off the road so much to find the wheel and buttons. There are some pretty big missing features that I miss from MFT, especially in the navigation system. Also, I don't understand how anyone can think that fiddling with the wheel and pushing buttons is less distracting than simply reach up to the touch screen (which is more in your line of sight as you're driving) and pressing a touch screen "button." Just pausing music is a PITA with the wheel. Again, I'll probably get better as I use the system. Voice commands worked much better for me with SYNC. I like the aha, Pandor, Stitcher apps in the Mazda3.
Also, does anyone know how to just turn off the entertainment system/stereo? It appears to have to be on some source all the time. Am I missing something obvious? Mute is not the same as off.
The transmission? In normal "D" mode, the auto transmission in the 3 is a bit better than the D mode was in my freshly-updated Focus, especially since the Focus tended to be a bit jerky at times. Throttle response is better than the Focus, and there isn't that annoying hesitation before the car does anything when you hit the gas, but I still don't think the D mode in the 3 is fantastic, just better and acceptable. Keep in mind that this is coming from someone who has always DESPISED automatic transmissions. However, Sport mode? Holy crap. No comparison. Sport mode in the 3 is a driving enthusiast's wet dream. I've never driven an auto that is this frickin' awesome to drive. I don't even normally feel the need to use the paddle shifters because it's so damn good at shifting on its own. Throttle response is almost as snappy as my Series II RX-8 (and that's really saying something), and it hauls ass in Sport mode! Even with 93 octane gas in my Focus (which would adjust timing to take advantage of higher octane gas) and the +9whp FSWerks intake with my Focus, the 2.5L 3 is noticeably faster than my Focus under most circumstances, and I haven't even pushed it hard, yet, since it's still in its break-in period. Does anyone know if the 3 will also adjust timing to take advantage of higher octane gas? The Focus Source Book stated it clearly (this is an internal Ford document meant mainly for sales people), and the difference in power between 87 and 93 octane was noticeable.
Handling and steering is a complex subject. I think my 3 has the best steering I've experienced in a front-wheel drive car, although it could have a bit more effort in my opinion (this was true of the Focus, also). I felt the same way about my 2005 3 (needed more steering effort at most speeds). The steering has decent road feel and is great in curves. The variable ratio steering in the Focus always felt just a little unnatural to me. I think I still like the overall handling better on my Focus with the THP, although I'm not totally sure. The Focus felt higher and tippier. The Focus was firmer, but also harsher on the terrible roads around Michigan. Also, the Focus understeered less. I think that may just be the fact that the roads have been wet just about every time I've driven my 3, and the front tires don't grip as well as the Michelin PS3 tires on the Focus, which were the best (summer-only) tires I've ever had. However, the Focus has active torque vectoring, and I don't think the 3 does. I'll be getting a thicker rear anti-roll bar quickly, I think. Because my Focus had the THP, it had a TERRIBLE turning radius. I knew that before I bought it, but it was still annoying. Nice to not have to plan so much to park, etc., in the 3. Overall, I like the steering/handling combination in the 3 better by a pretty good margin.
Miscellaneous stuff:
I love the headlights on my 3, and I like how they auto-aim around turns. I love the LED light bars. I hated not having HIDs on my Focus. My RX-8 has them as does my wife's new Lincoln MKX. I like the rear view camera. My Focus didn't have the parking package, so it just had the sensors (which were also useful). The Mazda3 has larger fender gaps. I'll eventually be lowering it around 0.5", assuming Racing Beat makes springs for it. I don't want to lower it so much that it becomes impractical as a daily driver in Michigan. Half-an-inch should be just fine. I miss the Focus interior lighting, especially the switch gear. All interior switches were light in the Focus. Most switches in the 3 are unlit, making it very hard to use them at night. Once I'm more familiar with the car, it probably won't be an issue. My 2005 Mazda3 was the same way. I don't miss the subtle clunking noise coming from the front suspension in my Focus, which the dealer refused to acknowledge even though there's a TSB on it.
And of course, it's a Mazda, which is all sorts of good!

It feels really good to be back in a Mazda as my daily driver.