I'm a current Mazda 5 owner, so am biased, but just my thoughts:
1. I'm a fan of the sliding doors. Some people aren't. It's probably a smart move for Chevrolet to not have sliding doors as it looks less like a minivan. I'd buy the 5 because of this feature though.
2. The performance in comparison tests doesn't really show the Orlando to be using any of its extra power, nor the extra gear to good effect. It weighs 50kg more in base spec than a 5 in base spec, but that can't be the only reason?
3. Fuel consumption seems poor for a DI engine with 6 speed auto. Again the 5 is actually better (marginally at 9.5, 6.7 - compares to 10.6, 6.9). Can it just be the weight?
4. I dislike the "tumble" of the middle row. It would damage cargo and I'd be worried about injuries. The latch system on the bottom of the seats. Do you know what I mean? I prefer the system in the 5; which reduces the height available when folded, but does hide all the mechanism and gives a flatish bulkhead.
5. I'd be interested to see some specs on the cargo area compared to the 5. Mazda quote litres to the window line, meaning a litres comparison is meaningless. The Orlando looks to have more room between the suspension intrusion in the back - I know my last generation 5 has 40 inches there. If someone could measure the width and height of the tailgate, the width between suspension struts, width over suspension struts, width at the middle-row and the length of the cargo hold with all seats, back folded, all folded, we could get a really good comparison going of the orlando versus the 5.
If Mazda can bring out a skyactived 5 they may be able to push sales back up. 155bhp, 150lb of torque, decent auto and a kerb weight about 50kg than the 2.5 should give enough of an economy gain to give up the extra power and really compete with other cars on fuel economy. Back of the napkin I'd predict 8.5, 6.0 for a skyactiv 5.