Otto's wont damage your plants...I have had them for some time now and they are one of the finest additions for a " cleaning crew " as you can get.
You wont be sorry you got them... I have 4 in a 30 gallon tank and they are busy 24/7 :hehe:
As far as the Sword price... thats a great deal for that size , I love my Amazons... I have to prune the hell outta them to keep them under control... I get new leaf's every 2 weeks... I wish I could plant them in my lawn cuz they would make wonderful shade tree's ! :hehe::hehe: