I agree in some way with all the comments that have been made so far. However, it has to be an individual decision about how you wish to market your business.
I am amazed that people choose to use "of the shelf products" that any tom, dick and harry can purchase at any high street outlet. By having products that are not readily available to the customer, immediately gives the impression that they are better because they have the words "for professional use only" (even though some are not)
Customers like the fact that we are not turning up with a bottle of W5 and asda's own brand polish. How do I know this I hear you ask? Because we asked them in a survey. 82% of the 105 customers that we asked suggested that it gave the impression of a professional company.
You will also find that the majority of commercial products are very cost effective, for example the polish that we use is water based (dilute yourself) and only costs 28 pence per litre when made up in a trigger spray.

Paul