IMO, too many buttons can be a detriment to the function of a device. The Naga has too many buttons - it just doesn't feel natural trying to thumb all those buttons. For me, the Logitech G700 hits every possible thing right. It's wireless and wired. It's got range-set DPI. It has the perfect amount of buttons and a great layout of those buttons. It fits great in the hand (right-handers only). And it has great software support (something Razer has always been terrible with). The G700 is just perfect.
I do have a Razer Nostromo, but I've had every iteration of the Nostromo since the N50 when it was a Belkin product. The fact that the Nostromo's form and function is so perfect is a reflection of Belkin's product design, not Razer's. The polishing that Razer has done to it is nice, however, and it is the one product Razer makes that I will stand behind. The software is lacking, but it works well enough to make the Nostromo hand's down the only gaming device I can't live without.
That being said, for ESO, I think the best input device is the Xbox 360 controller.