Having just bought a new 2820Vn after owning a 2800vg for many years I'm disappointed with the wifi on this router.

When streaming video from my Slingbox to my laptop, the video stops every couple of minutes. Am connecting using 802.11n, but when I disable N and connect with 802.11g it works without interruption.

Using the latest firmware 3.3.4.
Please fix it Draytek.

I've got similar experiences.
I often use PuTTY to run a command line interface to my server, and with 802.11n enabled, it is close to unworkable. It hangs for several seconds, then outputs everything I typed during the 'hang' at once.

It wasn't this bad with 3.3.3 - although I did notice video hanging every few minutes with that version as well.

My wireless card: Intel 5300AGN (laptop mini-PCi card)

My laptop driver is 5100AGN.

Another problem I have discovered; my Blackberry 9700 keeps losing WiFi connection, even on 802.11g.
Worked fine with Vigor 2800VG.

It's working for me with a 5300AGN and 3.3.4, I've only seen very occasional drops, no hanging and speeds are normal. I do have my wireless network set to WPA2 only though, since it doesn't seem to work as well with WEP/WPA (although 11n isn't meant to work at full speed with WEP/WPA).
I have a fairly simple network on the wireless side of things, only a few laptops and an iphone connecting at 11g, with one or two at 11n.

edit: I take it back, I'm having stuttering and speed issues now with 3.3.4, just needs more than one device on wifi...

Just bought a 5300agn card for my laptop hoping that I would see better results, but it still stutters on 11n.

I wonder if a different Wifi card like Gigabyte would be more compatible with this router? What brand of card is in the 2820vn anyway?

What encryption are you using ?

Are you using a wireless bridge on the sling box, I never had much luck when I used a wireless bridge.