TL;DR - The HR-V has better rear (actually pretty cool) seats and more cargo room. The CX-3 has almost everything else in its favor.
Pros for the HR-V based on my test driving experience:
- Those rear "magic seats"
- Cargo room
- green as an exterior color option!
- The head unit has an HDMI port, so if your phone supports it, with a $12 micro USB to HDMI dongle you can get your phone to appear on the dash, seemingly. However, the dash is not touchscreen, so you can't use the screen to control your phone.
- I do kinda dig the way that the speedo changes color to show how you are driving (economically, sporty, etc.) in real time (just about).
Cons (at least as compared to the CX-3):
- There is no good place to store your phone in the car. There is an area right by the HDMI and USB cables, but it is essentially UNDER the center console. You can't see your phone, and it is a PITA to even get to, which really limits the utility of the HDMI connection
- The styling is pedestrian. Not ugly, but VERY bland and boring compared to the CX-3, both interior and exterior
- The A/C uses capacitive, touch sensitive controls. I HATE that. It looks kinda cool, but it totally impractical. Want to adjust your A/C while keeping your eyes on the road? Sorry, but you can't feel the button, so you have to look at it to find the button areas and they are small so you have to make sure you hit just the right spot, but you didn't you hit another button by accident so now you have to try to hit the one that you wanted to hit in the first plCRASH! You just rear-ended someone.
- Interior is only available in black.
- CVT Transmission
- The driver's seat. This was the single worst thing about the car. I had a totally open mind. I expected the car to be worse, and came away impressed overall, except for the seats. The cushioning is rather thin. In Rush hour traffic I spend anywhere from 1-3 hours on my commute home. I don't think my butt would survive a 3 hour drive. With such little cushioning right in the tailbone area of the seat, it almost felt like I was sitting on wood. And this is with a brand new car that only had about 5 miles on it! I tend to keep my cars for a long time, and imagine5-10 years from now. It will be like sitting on concrete for hours a day. This was a total deal breaker, but it doesn't end there. The underseat area is really weird. It is not flat like normal cars, but it actually rises up and inch or so under the seat. It actually starts doing so BEFORE the seat (I had mine back, but not all the way. I'm 5'11.5". So what happened was when I tried at a stop to put my feet almost under me slightly - sit with my legs so that my shins were running parallel to the ground, I couldn't. That rise in the floor prevented me from pulling back my feet that far! It was weird and uncomfortable and seemingly not well thought out. Ugh.
CX-3 pros (based on viewed specs, and testing out the other current Mazdas:
- The interior is far nicer. WAY nicer!
- The exterior is distinctive, and it doesn't blend in with the background and 500 other small cars like the HR-V does.
- Better engine
- Supposedly much better handling.
- NOT a CVT transmission!
- 2 color options for the interior
- when it comes to options like parking/cross traffic sensors, lane departure systems, etc. Mazda has features that the HR-V just doesn't have (nor any of their other competition)
- Roominess in the cabin
- crappier rear seats by far
- Less cargo room both with the back seats up and with then down.
- Colors seem limited
- The Wait
HTH a little bit.