Almost all phone systems* manufactured today have Message on Hold capability, but to determine exactly what you have before your purchase a Message on Hold system, it is best to check with your phone system vendor. Need equipment?
A typical Message on Hold program is 4 minutes long. Because a voice over talent typically reads between 100 and 112 words per minute, the script for a four-minute program can be up to 400 words, allowing for four to six paragraphs or messages, interspersed by brief intervals of music. Longer audio storage and program lengths are available if necessary.

I haven't used this device for an extended period, but since there are no mechanical parts, I expect that it will last. We have been using a professional on hold service for many years at about $60/month. The box that the professional company gave us sounded great when customers would call from a Lan Line. But, when calling from cell phone the voice messages were lower volume and the music would sound horrible. Music keeps cutting in and out and sounds very staticky. So we decided to save some $ and cancel our subscription and buy this unit. We are using the default music and voice messages that came preloaded instead of doing our own music and messages.
-88% of callers surveyed want to hear product information on-hold and will stay on the line longer if provided with this information – roughly 16-20% said that they have purchased additional products based on information they heard while on-hold.