If you are just one of the bunch who doesn't have enough courage to play without premade, I recommend you to play horde. The previous 2 guilds mentioned before are good reference since it's very strange to see one of their members to play without premade (there are more, but I won't mention them).
That's mainly because of 2 reasons:
1. In alliance, premades generally are made through asking for people in global chat, not from guilds like in horde, so in order to create a relative fast premade, you need to lower your ilvl/skills demands and play with people you don't know.
2. Since in horde queue time is almost instant most of the time, is easier for them to sometimes even make double premades (***** ones even make double geared premades).
That's why there's no better experience than to defeat horde premades.