Well, having owned a 3 for 3 years (and the 5 being essentially a 3 with a van body, with an even plastickier interior to save some cash), I'd say it's a pretty good choice. Even though it's plasticky, they tend to assemble their cars properly, so you shouldn't get much rattle (and I've ridden in one with a few Kms on it, no rattling to report).
If your choices were ultimately narrowed down to the 5, the equinox and the tuscon, the 5 is definitely the best choice, especially if you enjoy driving a bit. Yeah, the engine isn't the peppiest thing in the world, but it's enough....whereas I'd say I grew up with a brother, living with both parents and grandmother, and we fit all 5 of us into a Nissan Micra just fine, so you don't REALLY need more than a good mid-size sedan.
