We have an S10 as part of the filtration on our 12 long and it seems to move a reasonable amount of water for what we are using it for. We haven't owned it long but so far it seems like a nice little unit, it's quiet and doesn't need to be primed and played with after a power outage.
Some people take aquaclear sponges and slice them in half to use instead of the overpriced cartridges or other people ziptie filter floss onto a gutted cartridge.
I also use one, the s15 and it is the best filter I have ever had. I just replaced the filter media it came with with some ceramic rings and Eheim substrat pro, plus some carbon and filter floss and it's doing very well.
I've been running the S10 for about a year now. its great little filter. i've run it on a 10g and 7g, it gives plenty of flow, i actually turned the flow rate down because i felt like it was to much for my little 7g, but was perfect at full throttle for my 10g
still quiet as the day i bought it. it comes apart very easily for cleaning. and there is plenty of usualable space in it filter if you want to add extra media.