Thank you for posting, apologies on the delayed response. The decision to upgrade is completely up to you and your company! As it relates to SPS Commerce, WebForms will function on either Operating System. Personally, I have not upgraded any of my machines, but I have heard positive reviews on Windows 10.
If you do decide to update to Windows 10, please note that WebForms will not function on Edge, the newest Microsoft browser, as the java plugin is not compatible. You will want to continue to use Internet Explorer or Mozilla Firefox when within WebForms.
I hope this helps, please let me know if you have any questions.