I had fabulous luck with my otos. They have a pretty high mortality rate, but I added them into a fully cycled, two-month old tank in the middle of an algae bloom, and all three survived and are flourishing. I think adding them after the algae bloom hit was what really helped them--they eat constantly, and that gave them a chance to eat all they wanted as they became acclimated to the tank. I just got my otos from Petsmart--nowhere fancy. I read somewhere to try to get them after they'd been at the store for at least 2 weeks, to help weed out the weaklings.
I no longer have an algae problem (they nipped it in the bud basically overnight), and they're still doing well almost two months later.
Once upon a time I had ludwigia. It disintegrated.