Hi there!
As posted above, Seraphic Nexus and RtS are the main PvP guilds (I have an itch that RtS is only accepting people Carthy likes, no offence). Notorious Synergy is a very progressive PvE guild but has a strong PvP side. Korvus is also pretty good, social/casual all rounder guild, more PVP as we aren't always on that side. Order of Chaos was a good PvP guild from what I hear but nothing like Cake is Real, not sure of they exist.....however just ask, some may require you based on skill and knowledge and there are some that recruit just for casual play, your choice.
Have fun choosing a nice guild!!