Agony in the flesh is a good arena for 1on1 and 2on2 matches, the aesthetic is gothic stone with fleshy bits. Some sections are more successful than others. aaaaargh! is a good map for 1on1 and very enjoyable 2on2. The aesthetic is relatively plain compared to the other maps. The rib cage is heavy on detail and looks very cool in parts but the game play is not as strong. The r_speeds also get a bit high. Tainted Crystals is the Clan Arena. This map has some really good structural and aesthetic features but the sometimes high r_speeds and weak game flow bring the game play down. Also there are connectivity problems that allow players to hide out and wait until the end of a match.
Worth checking out but may not make it to online servers. Great for LAN games.