I also have a 9010/9015. I say both because the only difference is the collection cup and I have both. I bought this skimmer because of the great reviews it gets and number one reason was the footprint. I will not do an out of sump skimmer and the 9010 was the perfect size under my corner tank.
I would suggest buying the 9010 over the 9015. The only difference is the collection cup. And for $100, you can always buy a new 9015 cup which is the price difference anyway. Plus, I just bought a slightly used 9015 cup for $50 bucks.
As far as my reviews, I was really impressed with this skimmer when I first bought it, I was getting 200ml of decent skimmate every day on a system that did not have a bioload, eventually that amount went down. I decided that I wanted to wetskim, and the best mod for that is replacing the stock standpipe with a diy adjustable. Once I did this mod to the 9010, i pulled out about 600ml of wet skim.
Then I decided to buy the 9015 cup. This did not work well with the DIY standpipe, but does work great with the stock pipe. I was getting about 100ml of dark green, not super thick, but definitely stinky green skimmate. Right now I am back with the 9010 cup and the mod, but that is because I want to wet skim for a while longer until the p04 in the rocks is taken care of. I will eventually go back to the 9015 cup.
Also, cleaning this thing is nice, because there is no adjusting the height of the cup after you have to empty it. Also, I consider my bioload pretty light with only 5 smaller fish, one star and about 2 dozen snails/crabs. I only feed once a day, and follow the 2 minute rule.
My .02, hope it helps.