It's the cheaper one! the M1000, Honest.... The £150 jobbie (Cheap! Ha!).
Before I saw this thread I'd been getting a bit fed up with the amount of CDs that I had on show (5 to 600), particularly when I had all of them on my PC (Euww.. Pc, yuk!) and having gone Mac recently though that with Airport and my WiFi connection, there had to be a better way of doing things. Anyway, your question kind of spurred me into action.
Picked the ROKU becasue it was the cheaper of the sort of 'out of the box' options and was available off Amazon. It now comes WiFi enabled, rather than previously when you had to buy a WiFi card to put in it. It's also really well rated by What HiFi (5/5 I think).
Anyway, plugged the Roku in and it boots itself up after 10 seconds or so. I guess it's about the size of two normal cans of coke end to end. Comes with 1)WiFi 2)Ethernet connection 3)Optical link 4)Digital out 5) Standard phono plugs and a rubber base that it sits on. Comes with a remote control too.
My home network is set up allowing only those MAC addresses that it 'knows' to connect to it. Scrolled through the settings on the Roku to find the MAC address - really simple - entered it into my router and Bob's your uncles brother etc. etc. It looks like it will handle any security protocol for a Wireless network. The only other thing you need to do is allow file sharing in iTunes (if that's what you use).
So far, I've realised that, in my case, it runs through iTunes so that must be running on the PC for it to work. If you close iTunes, the Roku can't connect to your folders, so you can't access your tunes.
Lots of variation on how you set the display up - large or small text, song names, albums etc. It allows you to play your 'playlists' - basically it's a front end for iTunes (and not exclusively iTunes either) and a bit like running an iPod menu system - you can search by any variable. I can see what's playing from the other side of the room (all be it 15ft) without a problem - the iPod just didn't allow me to do that and I figured, even with a remote fitted, I'd never be able to scroll through my tunes on the iPod without getting up and gawping at the tiny screen.
The other point (sorry if I'm boring you here), is that you can connect to self powered speakers (JBLs or something). If you want a second one and get some additional speakers, you can run more than one in the house.
Anyway, it seems to be doing what I need it to do and is pretty slick with it. Almost wish i'd bought the one that handles photos and video as well, allowing you to display them on you TV!
Seeing as your in Guildford, if you're passing Kingston, give me a shout and you can come and try and break it (via the remote, not bu chucking it around)!