Hi, I've passed on lots of stuff through gumtree. I find that it's great for furniture and almost anything goes, usually the same day. It's not so good for smaller household items such as appliances or baby kit, so I still use eBay for those items.
State up front in the ad your price up front and that you expect cash on pickup. I find that a mobile number gets MUCH better response than an email address. People will tell you they will come to collect something and then you may not hear from them again, so I tell interested people that I will hold an item for them for a day, after which I will take other calls.
All in all, much easier than eBay, even though you have to sort through the responses yourself.