we use wowstead. everyone in the guild seems happy with it. manages dkp, loot, progression, link to ts server etc.
Raid Leaders also use some mod ingame which has links to everyones dkp. No idea what its called. Might be part of wowstead. You type !need in raid chat. After a period, maybe 1 min or so, the bids close and the system shows the dkp for all who typed !need to rl in descending order. RL can then distribute loot. You can also whisper !dkp at any time to RL and it will come and tell you what you dkp is.
Works for us.