One thing to watch out for on the Spesh HotWalk: the seatpost is limited in how far it can be lowered because the bottom of the seat tube is closed. This doesn’t apply to the Islabike Rothan, which can have the saddle much lower as a result. My two-year old isn’t exactly tall, but he’s not a midget either, and he didn’t take to his HotWalk straight off because his feet didn’t touch the floor when he was in the saddle. (I was quite chuffed with myself when I got round this without cutting the seatpost up by nicking a bit of tubing off my old lawnmower, which fortuitously happened to be exactly 20mm diameter, same as the seat tube.)
The Rothan also has a back brake, and will probably eBay for more when it’s been grown out of. If I was buying again I’d probably just get a Rothan.