Back pre-1.7 sprint, I was arguably one of the best strafers in the US.... and the keyboard that I used? A standard HP keyboard that came with my computer. My mouse? Some 2005 Microsoft thing with two buttons, low DPS, and a bad scroll. I racked up 500 wins, and a ratio slightly better than 1/5. Back when I did that, it was actually impressive.
Now, I use a worse keyboard, and it drastically affected my typing speed, but in-game, it didn't make a noticeable difference.
As for my mouse... well, I switched to a Razer Naga 2014 a few months ago. Do I regret spending some $80 on it? NO.
Having a gaming mouse has enabled me to keep up with people who use the fishing rod technique, 180 Flint and Steels, and all sorts of other fancy tricks using secondary weapons. I'm able to have various buttons assigned to the numbers 1-9. For the fishing rod technique in close-range combat, I'm able to hit one button, right click, and then press another key, and ta-da! The fishing rod technique, all performed on my mouse, and in half the time that it would take me to do it using my keyboard as well. Using my keyboard, I've often hit Q by accident, causing me to drop my sword. No joke, that actually happened to me during a clan battle once. ;_;
If you use it right, having gaming equipment can drastically change your range of abilities. From speeding up the process of executing a certain move, to simply enabling you to pull off a fancy combo that you couldn't do before.
My page just glitched, so I have to post this and then refresh the page. -.-