I like rotators for their collection of faucets; it makes it easy to go through a bunch of faucets at once.
What I don't like is rotators with bad UI's and slow loading times, and bad selection of faucets.
There used to be a faucet rotator called Bitcoin Hydrant that I really liked, it had a nice UI and the owner pruned all the faucets, but unfortunately, I think he abandoned the rotator.
That makes me think, how to rotators make money, just out of referrals?
It depends on how much traffic you receive. If you get a lot of traffic, you can gain a lot of referral money.
Let's say that a faucet pays out 200 satoshis/hour, and their referral payout is 20%, so 40 satoshis.
Now, lets say that you receive 1000 visitors, so that's 40 x 1000 = 40 000 satoshis.
Now, multiply that by 20 faucets, and that's 0.008 for no work at all.
Also, some faucets will pay out much more than 200 satoshis and give higher referral percentages, so there is a lot of room for profit.
Of course, the hard part is getting the traffic, which can be difficult.