In the past, saving a well worn pair of shoes or boots was a very frustrating mission. Freesole urethane shoe glue is amazing, and good for a lot more than shoes!
I've had a lot of success using Freesole to repair wetsuit booties, flip-flops, and a pair of Asolo hiking boots. The booties and flip-flops were both cases of reattaching rubber to neoprene. The hiking boots had a crack in the sole. All three have been held together wonderfully by Freesole.
Freesole is a urethane glue that remains super flexible after it cures. The Freesole creates a super strong bond between the surfaces and purportedly will handle extreme temperatures, and water, as well or better than your manufacturers glue. I believe it! The reattached soles on my wetsuit booties have lasted 2-3 months without peeling at all, with probably north of 10-15 hours in the water.
Applying Freesole is pretty easy. First, just clean the two surfaces you need to attach with rubbing alcohol. Next spread a layer of Freesole on one side, making sure to get good coverage. I then use binder clips to clamp everything together and simply set it aside for 24-48 hours. The glue takes a day to cure, but when it does the seal is as permanent as when the shoes were new.
You can get a few uses out of Freesole if you make sure to wipe the tip of the tube off, put the cap back on, and then stick it in your freezer! It'll keep if you are careful not to let it sit out for very long, and store it cold. The first time I bought Freesole I wasn't so diligent, and a small bit cured in the neck of the tube.
I'm pretty sure this is a very similar formulation to AquaSeal, made by the same brand. I've been using the Freesole interchangeably with it. Packaging states that adding Cotol-240 cure accelerant will speed the drying time, and add additional strength to the bond. I've used it on wetsuits and it does work, but makes the glue harder to work with.
You can fill in cracks, holes, and reattach separating surfaces with Freesole. There are plenty of videos about how to build up worn down soles as well, but I haven't tried it.