I have a 1520, I will be replacing it this year (Considering the HP) with a phone that will have Continuum but to be honest I am not 100% sure how much use I would get out of it, I have an HP desktop, A Surface Pro 3 and an HP Stream 7, I will probably get rid of the Stream and the 1520 so losing one device. They beauty of Windows 10 and I suppose other modern OS's is the built in cloud and OneDrive, so when I come home and sit at my desk and wake up my PC pretty much anything I have done/files created on the 1520 or Stream during the day have already updated to OneDrive so I can open them on the PC. OK it will be better once MS get the new OneDrive app sorted.
Whatever phone I buy, I will highly likely buy the docking cables/station, but will I use it much, not really sure.
However there are bound to be plenty of business applications for Continuum and I can think of many in the business I work for but our IT department has a real downer on WP. 1000 + PC's running 7, 0 Windows phones and no Windows based app for our services (Hopefully on way).
But if you keep it a secret and don't advertise your products, don't be surprised when people don't buy them.....................