I guess my old, dead, Realist was a good arco pup. Pretty dark. Too fragile for the real world of full frontal bassing. I have a busted one in my string drawer if you want to try to fix it.
I think that the Full Circle that one of my students has would be great. Sounds very nice.
I've used a K&K Double Big Twin for some time now. It doesn't seem to get much love, but I like it a lot. Almost invisible, nice balance, great pizz, great arco. I had the other one, that mixed the two K&K pups (what was that called?... oh yeah, the Bass Master Pro)... but I prefer the DBT by itself. I thinks it's underrated, and overshadowed by some of the other "name" pups.
Some of these things are great in concept, but really, the best thing is something that stays out of the way and makes the bass loud. I have an expensive AMT mic with a tailpiece mount that has been sidelined several times by a cheapo cord that breaks when you look at it sideways. It's on the bench now, again. Sad and frustrating. I'll most likely sell it soon, because it's useless **** when it's broken. I don't think I'm hard on equipment, but I work in an environment where people step on my stuff, and it's a consideration when I buy equipment. I can't even count how many times people have strolled over my cables and popped out the little clip that mounts the pup to the afterlength of the strings. At this point, I think my K&K, maybe fdeck's little preamp that he makes, and I'm good. No more headaches.
This is "jazz arco" in my case, but pups only exist for that application anyway..
Are you using a preamp?