My microscope was cheap, around 130$ or so, but it does the job. No need to have an expensive microscope. Sure it is better than mine, and I cannot see baterias because mine does not reach that level, but I can ID fish parasites like ick or velvet, and I can ID diatome and dino easily.
It was cool to see the black bugs (ok not so cool) to ID it and do the treatment with Advantage...
Here I took a video with my small kodak video cam..wish I had a microscope attachement because I did this handheld...not so easy.
http://www.youtube.com/watch?v=dGJu0DitJXk
but I am very tempted to buy that microscope you posted in the link... It's in my shopping cart...hmmm...pressing the checkout button....hmmm...