Looks at the reviews. One thing I notice that is different is Metronet uses CGNAT in atleast some places and charge 10$ a month for a static IP. Also, Metronet is Fiber so if Cox only offers cable/DOCSIS/HFC in your area then that is a big win for Metronet. Fiber has faster upload, less latency and less problems overall. Finally Metronet doesn't have a cap while Cox caps most area at 1.25TB. If you game or port forward then CGNAT may be a deal breaker but you pay more then 10$ for unlimited data with Cox so that may factor out. I would ask myself these questions;
1. How much bandwidth do I use a month?
2. Do I game or port forward anything(cameras, servers, etc)?
3. Does Metronet require you to use their router/gateway? If so, how much is it a month?