What stability issue are you talking about?
First thing you should do is follow Riv's guide to use your own router. With the crappy dir-615 out of the way, then you can do some actual testing. So we can b**** about stability, but at the end of the day we all know that default router is unreliable to do any proper assessment of unifi.
I can get 1.1 Mb/s dl and ul max.
When torrenting, this is not a surety because it really depends on seeds.
I tested speeds on what.cd private torrent tracker and i can get the full speed. I even managed to get max speed on demonoid which is kinda like a private tracker but not quite. Basically for torrent downloads, if it's well seeded, yes you will max out, if not, then no.
Right now i'm downloading a torrent and it fluctuates between 300 kb/s to 1 Mb/s but this is nothing to do with Unifi stability :/ (especially since i am not using their shitty router, mines an ESR-9850)
Using Jdownloader to download megaupload sources using a premium account, i can max out using 4 connections.
Mirc download via xdcc bots does not seem to be throttled. When downloading from a xdcc bot on 4mb streamyx i only got like 10-30 kb/s but on unifi i get the full 200-400 kb/s from the same bot. If you are wondering why that isn't near the 10mbps broadband speed, that is because mirc xdcc bots usually have lower upload caps then if you downloaded from torrent or direct download most of the time. Anyway my example is just to show there is no throttling active for mirc as of yet.
Currently i am satisfied with the dl/ul speed i am getting right now, although 10mb broadband should be hard capped @ 1.2 Mb/s, but the max i've seen is 1.1 Mb/s. They really should hard cap at the promised speed, and not just slightly below it like they always do :/ Maybe Riv can explain why it is like this.
As for IPTV, it streams fine with no stutter when using my Homeplug as i don't want long dangling rj45 ethernet cables stretching around the house.
Does fax work? Not that i have seen.
Iphone need a physical wire from the modem directly to it. So if you want to put the iphone in the living room, and the router in another room, you will have a small ugly wire dangling on the floor, can't be helped. Iphone wiring is the only part i didn't particularly like.
my 10 mb is being shared between 5 devices and there seems to be enough bandiwidth going around for computer users. I'm a downloader and the other users are mostly surfers. I segregated the bandwidth allocation to 8mb and 2mb. 2mb is used by all other devices, and mine uses 8 mb minimum reserved bandwidth.
I just give my setup as an example. If you want a bigger pie for bandwidth allocation, then you'd have to go for 20mb so more bandwidth to go around.
For web hosting, all unifi packages are fine since the uploads are same speed as the downloads. You can visit my website to see how it is like. I have some downloads available for the time being for testing web hosting speed, however i already setup a QOS to limit the upload for it
http://mognet.no-ip.infoThe only thing that could ruin unifi right now is cap if it ever gets enforced. Right now it hasn't yet :/
My usage for July has reached 152gb but no sign of any throttling so far

@blacktrix
If you already followed Riv's guide and it still does not work, i suggest you pm Riv for help. I'm using my own router and it works. My router doesn't even have any vlan sort of capability (not that i know anyway).
@calvin92
24/7 torrenting isn't really the issue, although i wouldn't recommend using the default dir-615 for torrents as it wouldn't last for 24/7 torrent sessions

What matters is the monthly bandwidth for dl/ul. Right now it isn't capped, but when it is, then people will start to cry. Especially when your sharing that pie of bandwidth with other users on your network.
The reason they leave on torrent 24/7 is usually because they are seeding. If your a member of a private torrent tracker, keeping your dl/ul ratio to an acceptable level by seeding is very important. Not to say there aren't people who literally download 24/7, but seeding is usually the reason and very important need for 24/7 torrenting.
stability as in the fluctuations of speed and the latency to international servers and stuff. Coz that is the only reason I will be taking UniFi over the Cooluni pack. I was stable and low latency. And I have a WR54GL here. Can be used as wireless access point and divide the bandiwidth through there right? Its flashed to DD-WRT btw.
I read a few pages back everybody say the speed sometimes fast sometimes slow eh. haha. Any users reporting from RS premium account?