I think the Tomcat is a great IK for the price, esp the current sale price. Even though it only has a 1 year warranty, it will easily last 5-10+ years with care, probably longer. If you want peace of mind with a 10 year warranty and boat that will easily last 20+ years, go with the higher end kayaks (Lynx, etc).
It looks like they're going back to the basic thwart seatback for 2012, whereas the 2011 has the Cheetah chair. Makes me wonder what else is different for 2012.
Depending on the age/size/abilities of your kids, as well as how you envision using the kayak, the tandem may be great or you may be better off with one or two singles, or even a TomCat LV. I picked up a TomCat LV since my youngest boy (6) was too big to ride in the front of a single with me but not big enough to control a single very well himself in class II/III. For us it's worked out better to have multiple single IK's versus a tandem and it provides great flexibility. That said, we primarily run class II/III day trips.