Comfort milk has been processed more, so it is easier to digest. It is thicker than stage 1, which may help with any colicky symptoms, and its composition means your LO is less likely to suffer with constipation too. I'm currently using the equivalent formula from cow and gate to relieve my LO's constipation, and it is working really well.
Prior to that I was giving him approx 1oz of cool boiled water per day, which was working, it's just that he hated it and screamed the place down. You could perhaps try that first if you didn't want to switch straight away. I know people who have used orange juice to make their LO's go, and it works, but personally I don't like the idea of it for younger babies unless all other avenues have been explored.
Bear in mind that comfort formula costs about £1 per tub more than standard, and that you will need to get the next size teats (if you're using stage 1 milk now) for your bottles because it is thicker. Also, your LO may end up taking less quantity because of the thicker consistency, so their weight gain may drop a little.
And also a couple of things it's useful to know when using comfort formula. Your LO's poos will turn greener, and at least to begin with will smell absolutely disgusting. I could smell my DS from downstairs when he was in bed with the door shut!
On the plus side, it was the reason my LO started going through the night
Also, when you make up the bottles, it looks like the milk has split - but it will mix up properly if you give it a good shake.