There's so much info on DLN you need read as many posts as possible then ask specific questions. Your question about going digital makes it appear you don't own a scanner ?
As far as working less hours, cad/cam allows you to grow the business, improve consistency, higher productive, lower your cost. I'm assuming you know this and more already ?
I maybe wrong but I think your not fully aware of how going digital changes everything in your lab. Spend time in a few labs with scanners only, and labs with a mill to learn more about what you don't know first before moving forward.
The mills you mentioned are all nice with comparable accuracy, and mill as well as mills costing much more. There are many owners of those mills and posts on DLN that talk about those mills and other great brands of mills.
I think the AG Cermill is the only one that mills sintron ? I maybe wrong ? and Sintron requires an expensive oven. If your going to buy the AG mill because of access to sintron, allow the extra $$ for the oven......maybe the extra cost is worth it if your doing a lot of pfms now and the future ?
Many labs but not all going digital are doing higher percentages of full contour restorations that's growing by the year, and that will also lower your labor/hours. The newer more translucent zirconias/emax is creating a higher demand for full contour restorations. My opinion is yes you could work less hours as improved materials are released and the demand for full contour crowns increases.
(Another item you do not want to skimp on price is an sintering oven..Don't make the same mistake as others on DLN buying the cheapest oven. )
More than anything you need to first decide if you want or need a 5 axis mill for milling large bridges, bars/ implants/abutments, and what materials you plan to mill for sure ! If your only milling wax, pmma and zirconia , any of these mills are fine alone with a long list of other mills. Most importantly you want to have the best support possible for all this new technology your about to purchase. Lastly, don't buy strictly on price alone, and ask other labs who has the worst and best support in your area.
Good luck