This toy arrived for my 5 year old today, together with a Gup-D. On balance, this is the better value of the two.
It lends itself well to imaginary play because both the front and back halves open up - the back revealing a control panel and 'tank' to put rescued animals. You can fit two or three of the characters in the Gup. Much Octo-fun to be had there :-)
It comes with a Captain Barnacles in a red jump suit. I wasn't sure about that because he never wears this in the series, but my kids didn't care. The character toys are nicely proportioned and pose-able and my daughter played with these more than the Gup!
You can wind it up for it to move along on the ground or in the bath but, in fairness, it's a bit big and heavy for this to work properly. It performed quite well in the bath but if you jiggled it around too much, it capsized. I think younger kids may get a little frustrated with this. It was reasonably easy to shake out the water - essential to avoid black mould ruining the toy.
The front hatch comes off quite easily, but is easy to re-attach. Not 100% sure if it will last the distance, but overall the toys seem well made.
At the end of the day, though, a good stab at the essential range of toys for Octo-fans everywhere...