Marui makes an M14 too, ya know. I'd imagine it performs well stock, but the G&G is better at its stock.
The question is kind of stupid. Each player has their own preferences, and can deal with the quirks their gun has. And depending on who you ask, most people don't have any specific brand. For instance, they might have a marui mechbox, with a G&P body, and a STAR Buttstock. But, from what I have seen, marui is the most common(AKs, P90s, M733s, stock M4s, and a few Mp5s).