I now have a 2.5GHz/5GHz (2x2) Broadcom inside of a new desktop computer and I'm looking into upgrading the upstairs router from the DIR-655 to something new.
Based on the reviews from within this forum, I'm impressed with this product.
Based on the reviews at Amazon, I have the following questions:
Is the firmware overly buggy?
Been good for me.What's the range? I'm in the basement, separated from the router by the floor/ceiling.
Definitely more range with this unit and most of the L series routers I noticed on 5Ghz. Even with the 826L the 5Ghz range is very nice. I watched a movie a while back between the 868L and a DIR-865L in bridge mode connecting in AC mode streaming raw BD files. Only a few bufferings seen however I think that could be attributed to the Boxee possibly connected to the DIR-865L. Definitely handles raw data better than N mode does. I could not watch a raw BD movie on 5Ghz. DVD Files are great on either frequency.What's the 5GHz range, practically speaking?
I watched a movie between the 868L and 865L and the distance was about 18ft If I remember right. Does the router really need to be reset (power cycled) daily or does it do its job over the long haul?
Haven't had to power cycle for anything accept for my configuration changes and testing.IPv6 compatibility?
Hope someone else can chime in on this. I don't use IPv6. Yet. 
The Broadcom PCIe adapter inside of my computer connects at 130Mbps on 2.4GHz, which the DIR-655 can handle, but I keep getting a Limited Internet connection in Windows 8 (sometimes in a few minutes, other times up to every half hour). I have to fully disconnect and reconnect. I'm tired of doing that. I believe that the Limited Internet is from all of the congestion on 2.4GHz in this neighborhood - the router sees it all which I have observed upstairs at the router using a WiFi Analyzer app on my Android tablet. Perhaps the DIR-655 just doesn't handle that connected speed well, I don't know. Up until this desktop computer, I've always used the DIR-655 at the laptop's 65Mbps which continues to work well.
Adapters are only limited by there design in connections. The 655 can do 300Mb connections however the client side HW has to support it. To get 300Mb connections on WiFi, the router needs to be set for Single Mode N, WPA2/AES Only and Auto 20/40Mhz. My Mac only supports 130Mb on 2.4Ghz. I have to use a different adapter if I want to see 300Mb on 2.4Ghz.I'm thinking a better router may help on 2.4GHz. But mainly I'm interested in using a 5GHz connection between the basement and upstairs which I'm somewhat directly below the upstairs router (somewhat).
Need to place any WiFi router centrally as best as possible in any building for best coverage and range. The add on additional WiFi extenders if needed.In order to resolve the Limited Internet connectivity issue, I've placed the DIR-655 into wireless-g only and the connection on 2.4GHz with the desktop is rock solid.
Over all I'm liking this router all the time. Currently using it until I need to test something else or when the new DGL-5500 comes out. 