Factory pickups vs. after-market pickups

I'm looking at getting a new tenor with a pickup. I currently have a uke with a Baggs 5.0 installed but I was wondering how the factory installed pickups (Kala UK-300-TR, Shadow Nanoflex, Fishman Kula) compared to the Baggs, or any of the other after-market pickups (K&K Aloha Twin, Big Island Spot, MiSi).

Does anyone have any pointers to audio comparisons?

Thanks!