They're a lot of fun.
We started these as we do all of our construction sets - separating the pieces by color for easy building. Now, these are smaller "starter" sets with just 71 & 73 pieces, respectively, so they're not a particularly time-consuming, nor challenging build (they have bigger sets for that), but the amount of reaction out of Addie - the sheer enjoyment she's been getting out of them - has been surprisingly above average.
High Flyin' Sin Cara was the big winner right out of the gate, with it's launching action able to make Sin Cara (or any other figure) go flying through a break-away "Ring of Rampage" with ease. While that set scored bigger that Sandrow's less-action-packed classroom of sorts, the 12-point articulation of the C3 figures makes them pretty unique in the construction category, complete with little "Snap-Fit" spots that let you connect the figures for some brawling action.
Yes, it's fun for Dad, too.
We've had this pair of StackDown sets built for nearly three weeks now and there's no sign of tiring on them. These guys have been mixed and matched, customized and rebuilt quite a few times over. One magic question that I get asked almost without fail on the building sets is "how do the bricks compare" to that other outfit with the little yellow figures, and that's always a loaded question because no one can duplicate the famous, yet proprietary process that the big boy uses to make their bricks so accurate during production. So yes, there is a difference in their feel and performance, but it in no way hinders the enjoyment of the sets.