For those of you who are unsure, 'Ugg' boots originate from Australia and are made from sheepskin. UGG (in capitals) are a brand name for Ugg boots, as are Emu, Ugs&Kisses, Love from Australia, SN'UGGS etc...
I already own a pair of UGGs and love them but can't afford to spend that much on another pair so I looked at other brands. These Emu Stinger boots are perfect and comparable to UGGS in every way. The quality is the same and they look identical. If anything, I would actually say the soles on Emus are better than the soles on UGGs.
With regards to sizing, I am a UK6 and wear a UK5 in UGGs as they are made in US sizes and they are not converted to exact UK sizes. I ordered UK6 in these Stinger boots and they do fit although I am tempted to try a 5 as I know they will stretch. (Im not sure why people have said they are small sizes, I haven't found this to be the case at all). So my advice would be to order your own size. If you are half size I would be tempted to go down a size otherwise you will find that they feel loose once they have stretched to your foot size. These are definitely better quality than Emu's Bronte and Chalet style boots.
PS. Would also like to add, they are quite wide fitting so if you have narrow feet you may find them a bit loose.