I have CB and Xfinity. I'm told the same as the residential plan. So why am I switching to CB for about 100 dollars more a month?

The Comcast business comes with a netgear box that has Comcast Business stamp on the bottom. So what is the difference? Can I just go buy a good router and modem and run it myself from the 1 cable coming in from the pole? I run everything Hardwired. Only the Living room TV and phones are wireless. So what is the uptick for CB? At 79 bucks for 1.25gig (of which I only see maybe 900 at best)  from Xfinity or 159 a month for maybe 1.2 gig  at CB. I'm on a 30 day trial period and have not noticed any changes at all. We don't have Fiber in this area -and was told by any of the techs that knew -we were NEVER going to get it here. I'm doing alot of 3D modeling online for my business(Engineering/Arch). Lots of big file transfers. And Have 2 NAS servers and 2 Desktop computers in my Home office. I was told that it would be a separate/direct line in but all they did was put on a splitter.  So what is the truth? I need several static IP's for the servers to use. I know I can buy blocks of them from CB. But I'm not bringing in that much to spend it on even more  equipment or services. Please Advise.