I used DD-WRT on a D-link router to repeat optimumwifi. It works fine. If you have a login for Optimum, save the WAN-facing MAC as one of your devices on their site for a connection free of intrusive login prompts. Other tips: use routing rather than bridging, use a SSID other than optimumwifi for your private side of the network and encrypt it with WPA or WPA2 so others in your vicinity don't use your repeater without permission. You'll be able to connect multiple WiFi devices within range of your repeater and you can plug in multiple wired devices such as VoIP adapters like Obi.
used a similar arrangement to extend a network borrowed from a neighbor. used native router firmware (tp-link) to create my own network. my obi is plugged into said router.
some dchp tweaking to assign IPs in the same subnet as orig. network but different range (so as to avoid conflicts).
now if only I could solve the constant 'unidentified network' at my favorite optimum hotspot... (I need to 'diagnose network'/'correct ip config' 3-4 times an hour...)
