Id go for Amano, I have 3 in my 300 L but obviously you would need more than that to make a dent in any of their cleaning duties!
mine eat the dying plant matter, algae and the odd BBA- although they only chomp down on that once a month or so, they also eat left over food, and clean the filter out take, they can also hold their own against bigger fish-i have mine in with giant danios and tetras, and corys but I did grow them out in a breeding net and released them when they were around 3-4cm so they couldnt fit in hungry fishes mouths!
I have them in soft water and they have taken up a blueish appearance, they are quite pretty...the only down side is that they are quite hard to get hold of in pet stores.
oh yeah, mine are quite ballsie but when I first let them go in the big tank they were hidden for 3 week, I thought they had been eaten but they proved me wrong