The colourisation is brilliant and produced absolutely excellent results.
The AI is very effective at applying colours in a very realistic way. Often colorisation jobs end up obvious due to very slight telltale signs like too much saturation and too much colour consistency. Object's colours vary in hue as well brightness across their surface, and this AI is very good at estimating and replicating that variation to brilliant results.
However the main issue with this colouriser is the lack of customisation. This is something I hope that will be added, but right now you have to live with the AI's choice of colours. For nature pictures this isn't so bad (grass is green, sky is blue, etc.), but when you colourise photos of people, or buildings, or anything really that you know should be a certain colour, the AI's often gets it wrong. It would be great of having some way of guiding the AI, saying that this is red, that is blue, this door is black, her eyes are blue, etc.