Are you a laptop user? I guess that if your computer does not have a full keypoard and the roguelike does not require you to often use lots of non-directional keys, then a gamepad indeed should be better than other options (playing on the laptop keyboard itself or attaching a full/numerical keyboard).
Yeah, I'm using a laptop. The lack of numerical pad is the main reason I tried looking into using a gamepad.
What do you do if the game requires you to use a non-directional key? I guess you can also map the most frequent ones to the gamepad (like fire in DoomRL), but what about other keys?
I map all the keys needed to the gamepad with xpadder. a logitech dual action gamepad gives 12 buttons total and each direction of the analog sticks can be set to a different key. You can also set a specific button to switch between different key maps. so in the first key map, button 1 could be used to pick up items. Then I could press the button to switch key maps, and button 1 will do something else. Then switch back. I usually use the two left shoulder buttons as the "shift" key and a button to switch key mappings.
I don't bother with every single key, but the majority of them.
Using a gamepad is very comfortable and I prefer it to keyboard now. It's also fun when using a gamepad and hooking up my laptop to my tv o play on a bigger screen. like playing a Rogue on a game console. The only tricky part is trying to remember which keys are mapped to which button at first but eventually it gets memorized.
xpadder is a free program that lets you emulate keyboard and mouse to a gamepad in case that wasn't clear before.