Setting up the n52 was easy, although substantial changes were made to its default WASD-style setup. With fifteen buttons as well as a directional pad, scroll wheel and orange thumb button, the most obvious mapping seemed to be to assign the numbers 0-9 to buttons 1-10, with the other keys reserved for shift, information panes such as map and bags, and jump.
By spending some time tinkering with both the n52 Profile Editor and WoW's keybindings, the pad was ready to prove its worth in real combat.
Initially trying it out is quite awkward, and I had to change my action bar layout (which was on two rows of six buttons previously) because of the mismatch. Fortunately, most of the time I only end up pressing a few buttons repeatedly while playing, and it was easy to keep hitting them. When healing, with the fantastic BeneCast addon, I did a lot of mouse clicking and a lot less button pressing than in other forms of combat.
Using the directional pad for movement isn't so easy, and even after a few hours' use I couldn't quite move freely with it. I tend to use both strafing and mouse movement to get around, and I haven't quite got the hang of pressing the pad instead of using WASD. It's definitely a point to persevere on, and possibly experimenting with different profiles will help me customise the n52 to work better with movement.
Overall, it was definitely quicker to use the n52 during fast-paced repetitive combat, but it requires a large investment in terms of profile and keybinding customisation. It was great while soloing, as my hands didn't have to leave the n52 and mouse at all, but once I got into an instance I found myself moving to and from the keyboard a lot to chat and emote. The pad has three configurable shift modes, meaning that I can map emotes to the various buttons and use (for example) the orange thumb button to temporarily enter 'emote mode'.
It seems the main drawback at first is simply keeping track of which button does what, as well as the various shifts. There is no workaround for the lack of chat, though clever macros could mean your most frequent sayings are but a button-press away. If you talk a lot (alongside combat) then you'll find your hands moving a lot, but after an initial outlay in configuration, the n52 brings a lot of efficiency.