I have always loved the Iorwerth. I believe this is due to RuneScape gold the fact that prior to the final quests of the Elven questline The Dark Lord was always considered to be Zamorak. I don't know if it is real however I believe that certain NPCs are referring to the Iorwerth in some way as Zamorakians who revolted against the crystal goddess-led Elven society. I feel for Lord Iorwerth's Elfs because of this.
The clan is now under new leadership and is trying to get back into the elven society. They're a belligerent clan, which makes it hard to disliking them. Also, they have a wonderful clan crest.
Clan Cadarn (the second largest civil war clan) is one of my favorites. They are a bellic clan, which is the exact opposite of the Iorwerth. They are more focused on the magical and stealth arts rather than brute force like the Iorwerth. The clan is focused on my two favorite skills, that is always a plus however I'm not an avid fan of the crest though.
For clan leaders, I'm a big fan of Lady Hefin Lord Amlodd and Lady Meilyr. Lady Meilyr's overall appearance is exactly what I love. She appears like a hippy elf. She's very high when you first meet her. She is also among the most valuable leaders of elfs, with all of the Herblore (especially the ones which were bought at 10Mish and can't wait to use them) and Dungeoneering items.
Lord Amlodd is a similar character, appears quite cool and appears to be the least serious of the clan's leaders. I also like the clan's crest. Lady Hefin is a favorite of mine. I find it remarkable how young she is because of prayer and healthy eating habits. She is also an exercise-oriented priest who is at the gym each day and doesn't age. There are other clan leaF2P PKing ranged was the normders that don't age too or age very slowly as Lady Trahaearn and Lady Meilyer, however they make use of the same potions and techniques to buy RS gold achieve this effect, which isn't near as cool.