1. Is a certain hardware version better? I have A1 and it seems like a lot of guys with A2 are having better luck with it. I may go buy one with A2 if this is the case.
Unless you're buying second-hand or from someone who has a large stock, I would think all of the new units are delivered with HW:A2. I'm running a HW:A1 FW:1.02, and haven't had any issues with it, but I don't use a number of the features including Gamefuel/QOS.
2. Gamefuel vs QOS. If they are the same when setup right why wouldn't users go with the DIR-825 over the DGL-4500 since you would have simultaneous dual band in the DIR-825?
Well, the DIR-825 doesn't have the OLED display. Although for me, the sticking point is the firmware design. The DGL series firmware is just cleaner than the DIR models I've looked at. I'll admit that I would like simultaneous dual-band, but it isn't compelling if I have to interface with the DIR firmware. It just comes down to personal preference for me. Maybe others as well.