From what i have read from other forum and other internet source, they sound like a bad idea to keep.
1. They do disturb other bottom dweller
2. they will mess with live plants; eating them, up root them, and what not.
3. they reproduce via parthenogenesis which mean if even one escape they can reproduce in the local water shed, upsetting local wild life. Not only that, they also reproduce rapidly.
That's what I've heard as well. I heard that they can kill any fish that they catch as well. That's why I decided not to get one even though they look cool. If I had a species only tank for them, I'd consider it. Maybe. But if I did get one, I would be especially careful about keeping them in the tank and not letting them get into local waterways.
I have one and there great.She will eat plants and shred them without even the slightest thought.Mine got mad at all the java moss in her face and stuffed it under a pot lol.Mine is only now berried and i have had her for almost a year.They dont seem to bother my shrimp either, from the tiniest to the largest.
I have one in a 10 gallon tank full of Endler's and Najas, haven't lost any of either as far as I can tell. I have 2 more in a 38 with a couple of small cichlids and hornwort, no issues there either. I really doubt they'd take over an established ecosystem if they did get out. They aren't an aggressive species overall, and wouldn't be likely to compete well against native critters.