If a company's products are designed and built properly using reasonable specs, there will be far less need for 24x7 support because there will be fewer breakdowns. Look at the products. Then review the product literature and the marketing materials. Most problems can wait till tomorrow morning, when the engineers get in after having breakfast with their families. Find out how the company wins bids against the competition, because you'll be holding the bag.
Customers eat it up.
Ask someone in sales how they won their last two deals. Higher quality might mean sending in the engineers at 2 a.m. on Saturday morning. Lower cost might mean the engineers are salaried and there's no overtime for midnight rides. When we need engineers to be available 24x7 or to travel extensively or to work long hours, we hire them and pay them accordingly. They know what the gig is.