In this modern age, having equal upload/download speeds is a nice convience, especially with uploading streaming video. What is comcast's plan/when does comcast plan to offer these services?
DOCSIS 3.1 FDX will enable Symetrical gigabit connections over coaxial. The tech isn't ready yet, give it a few more years for CableLabs to finish it (The real driver in innovation that has very little to do with Comcast)
In the mean time, if you're already on a gigabit plan and are paying the ungodly $50 "unlimited data" fee, you might consider the "Gigabit Pro" plan if it's available at your address, which is 2GBPS symetrical fiber from Comcast.