I think it comes down to personal preference. Integrated are potentially more reliable (larger heatsinks) and can come with 10 year warranties and some decent designs, however they cost perhaps £7-10 more per light than a decent GU10 combination.
With GU10 you can choose the right bulb for the location and swap them about if need be. They also have a lower cost of entry as the fixings usually come with a halogen bulb to get you going, meaning you don't have to buy the LED bulbs all at once.
Personally I've gone the GU10 route as I want to use a variety of different power rating and beam angle bulbs and also be able to take the bulbs with me when I move to another property.