Hiya,
I agree with Fox on this one, people are fickle and if the "standards" of your company keep to the same, your customers will not mind at all.
The most important thing is that your customers have good contact with you on a regular basis, especially at the beginning of the transition. You will find that as time goes on the customers will contact you less and less.
I always make sure that I maintain a little PR excercise with all of our customers that we send staff to, at least a couple of times a month. Simple call just to ask if all is ok. Custy have commentd that this is a touch that they like woth us, and never had it with other cleaning companies.
Kind regards
Paul