Vantaggi
Ubisoft treats it's employees very well on the whole. I've never seen any requirement to crunch, there are fun events held in the studios and also outside of working hours, and there is a mountain of talented people within the studio who are experts within their field.
Svantaggi
Pay is very mediocre, and doesn't increase much with time. If you join on a low salary, you can likely expect it to stagnate for quite a long time. There are people within the studio who are still significantly underpaid, and they are unlikely to be paid their value until they move to another job. There is a bonus scheme, but you'd be very lucky to get anything from it. There is no requirement to crunch, but your workload increases gradually as time goes on and you can't possibly get everything done without working extra hours. There is a large meeting culture at Ubisoft, where meetings seem to be required for every thing, regardless of how large or small.