Funny... I just listed a stack of household stuff on gumtree for the first time. 3 items have sold same day as listing, all for free. I have noticed that there are a lot punters on there that try and play hardball with you, though. My brother was telling me there are professional 'pickers' that try and low ball you for instant resale, concentrating on the new ads. Anyway won't be going back to ebay for selling in Oz. 
10% percent fee to Sell on line...what particular infrastructure do they supply that requires this margin?. Is all the stupid adds not enough.
Truth is ebay has becomes another source for listing actual shops and businesses, hence they don't need the individual seller anymore.
A brave new world with more human beings than ever and yet owned by a fewer and fewer individuals.
They are all the same company ... 
- eBay
- gumtree
- paypal
- craigslist
- skype
So by "leaving" ebay, to use gumtree ... kind of makes no difference ...
en.wikipedia.org/wiki/List_of_acquisitions_by_eBay
If it becomes a pain in the arse and they do start overcharging, someone will undercut and make a new product that is reasonable and ebay sadly and gumtree if they go down the same path will be forgotten.
Much like the trading post has as it overcharges IMO.
