Gorilla, as a PU glue, has numerous properties:
It's gap fillling, but it provides no strength in the gap.
It's water-proof (not resistant)
It stains your hands like nobody's business
It foams, so if you use too much, you have to clean off a load of excess that's foamed out the side of the joint. You know if you've used the right amount when there's minimal cleaning up after.
It's mono-component - one bottle, apply glue to ONE side of the joint.
Don't use it with biscuits - biscuits work by absobing moisture to swell and fill the biscuit slot - PU glues cure by taking moisture from the surroundings, so using the 2 together gives contention for the moisture content of the wood and also the atmosphere
It's pretty strong - but I've heard that it doesn't live up to claims of 'the strongest glue you an buy'. It's also considerably more expensive than other PU glues with similar, if not identical, properties.
If you use it, make sure you squeeze out as much air from the bottle as possible when finished, cos it will set from the moisture in the air remaining in the bottle.
Shelf life is not long. (3-6 months, IIRC)
That's about the extent of my knowledge on it.
Oh yeah - Isaac Lords have started stocking it, though may not be available from their web-site, which is driven by their trade counter, and which used to stock the same PU glue as Screwfix sell.