Used one years ago, when we were young and foolish lads - they are indeed stable, very light and unsinkable; must be, 'cause we're all still alive. Two adults is just fine - lots of carrying capacity. Re handling - remember it as being slow - due to wide-ish beam. Both the SportsPals I've been around were light, riveted aluminium hulls; they both developed leaks, mostly from the rivets working over time. They dent easily. Repairs of torn AL, at least for folks like me who know fibreglass or stitch&glue construction, is difficult. I wouldn't say they are especially durable, given the lightness of the metal. I don't know about using motors, 'cause we 've never used one.
For the purposes you mention, a Sportspal should be OK - but I'd be leery of using it for river work if there are any rocks that could cause damage. I'd suggest treating it as you would a cedar canoe - don't beat it around any more than you absolutely have to, generally treat it gently -(we sure didn't :-)), and you should have a nice little boat that'll certainly let you and your family decide if paddling is the sport for you.
If you're looking at a new canoe, the price of a new Sportspal might be comparable to that of a decent used cruising FG or Royalex canoe that would have a lot more 'growing room' than the Sportspal. Expect to pay a weight penalty, tho, if you go the used FG/Royalex route.
Regards,
Rick

Know Your Boat, Know Your Waters, Know Your Weather and Your Limits