I have the Super Mable and I wouldn't recommend it for the following reasons.
-it sinks VERY easily and often if you're riding with the curved part back. it likes to submarine for some reason
-it is VERY easy to catch air under it and flip it over. you ever try to flip a giant sized, soaking wet tube back over while you're treading water??? you can't--gotta drag tube back to the boat and flip it over from the swim deck
-it's freaking HUUUUUUUGE (yeah, I know, not always a negative)
-there is no quick disconnect built on it so you need to buy one or else good luck getting the rope off the attachment point
-riding it solo is next to impossible since it flys away so easily
on the positive side:
-if your kids enjoy going SLOW it's a fun tube to cruise around on
-if they like to wrestle or king of the hill while at anchor, it's a great tube to play on
-if they like to ride it on their knees (curved side forward) it's a fun tube. my kids complain their feet,knees, back hurt too fast that way
I have two small one person tubes that I use 99% of the time. the kids and adults like to battle to try and knock the other off.
just my $.02