I used Swisher once for about 6 months on a 7 day a week contract ( Swisher came in and did just the toilets and urinals once per week ). They did a fantastic job but they are expensive. They didn't use any fancy equipment, just chemicals and rubber gloves!! The loo's always looked like new after they had finished.
I would use them again on this type of work, but don't feel they are needed every week, if they would agree to once per month I would use them more, but our local chap wants a weekly visit at the least.