The move from a Freestyle to a 5 makes pretty good sense considering they are both kind of a sports-activity type vehicle offering both car-like characteristics and van/suv type versatility.
The Freestyle will definitely offer more room in the 3rd row, as well as more cargo space with the 3rd row up. If you are going to be putting less than 5 people in the car though, this point is pretty much moot because the 5 offers plenty of cargo space with the 3rd row seats down.
You may find the interior of the Freestyle to be a little more appointed, but the fit and finish of the Mazda won't disappoint. Everything feels decent to the touch and is nice and tight.
Reliability in the 5 is generally a non-issue. In my opinion the common gripes about the vehicle are very tolerable and are a more than fair trade-off considering how fun the 5 is to drive. Tire-wear due to camber issues, a few random suspension problems, and reports of power-steering failure are the main ones. Most times these issues manifest themselves early enough into the life of the car that they can be fixed on warranty. But even so, I intend to replace my stock suspension immediately after warranty runs out with something after market that will be bullet-proof and make the car even better to drive. Also fixing the camber issues in the process. Power-train is a non-issue.
The main difference between the Freestyle and the 5 will be in how it drives. The 5 will feel much softer sprung then your Speed3, but the steering inputs will be very similar, as will the pedal position. The steering is really precise and sharp so the car feels agile. I dare say that on a twisty back-road, with some stiffer springs the car is as fun as many sports-sedans, more fun actually.
The car is heavy but feels light because it changes direction fast and is so easy to control. It's got brilliant visibility too which makes parking downtown a snap.
Sure it's not a strait-line performer given the weight that the 2.3 has to push around, but we consistently make 24-25mpgs in the city and over 30 on the highway so I have no complaints. Still the engine feels torquey enough to pass confidently, just don't do it near the top of an incline
Overall I love the car. I know which friends to recommend it to as well. If they just want an A-B car that will never let them down then of course send them off to get a Matrix or a Honda fit. But if they actually care about enjoying driving then this is it. Plus the reliability is still excellent.
As you can tell I love mine, as does my wife.