Sorry about not updating this for a while - crazily busy week at uni.
I have indeed heard the Neo's , they are currently in my houses shared area on the end of NAD rocking out. Great speaker for the cash. I also still have the 684's on home demo, and am loving them. They have improved massively over the week as they have run-in(I was the first person to get them out of the box) and now sound fantastic. They are a really neutral speaker and all frequency is reproduced well, they really remind me of the Genelec monitors I have the pleasure of using at uni. The really let the qualities of the Roksan shine through and for a floorstander they really keep timing excellently. The only small problem with them is they seem to struggle a little with massively distorted music, one of my house mates is into death metal and when I let him listen to some of his music they 684's sounded rather muddy and boring. However they sound fantastic for my kinda music so this doesn't trouble me.
As i'm sure you can tell I am rather keen on the 684's and have been offered them for £550 brand new. I am about 80% sure I'll go for them.