I sew in the basement, but it is an actual bedroom with a 4 foot window and southern lighting. It sounds like your current room doesn't have a lot of light, so not that much different from where you are now. My sister also has a sewing room on a northern exposure. She has a large shop light directly over her sewing table and cutting tables - splendid, splendid lighting.
The only disadvantages of having a sewing space in the basement, in my experience, is access to phone or door. You can have a phone line there, which eliminates one problem. If you get a lot of visitors, it may be a hassle running up the stairs to the door. On the other hand, the exercise is helpful (I keep telling myself that). If you have an old dog, you might want to put an insulation layer between the floor and the dog bed to keep him or her warmer.
Another tip. I found it necessary to wear insulated slippers on the basement floor in winter. Over a couple of hours of sewing, my feet got cold, even with loafers. Doesn't happen with sneakers, but I don't sew so well in sneakers due to the thick layering. So, I just leave the sneakers at the door and put on the slippers.