The automatic download is known to be infected, so do not download it.
Most add-ons seems safe, as long as you download manually.
I'd Recommend downloading add-ons straight from their source instead of here.
I Know for a fact that this is not the Justdubs site that was closed..
I'd advice against using this site, since they're trying to use justdubs name to get visitors, meaning there trying to feed off of what ounce was and most likely has a virus there.
To sum it up:
This is not related to justdubs.net
This site might contain a virus.
a few of their players are known to be dangerous (please use McAfee site adviser it will block them.)
The adds are usually safe, but should use Adblock plus to block them (this also blocks the pop ups)
only problem I've had so far is a malicious attack from the blocked player from ip address 188.8.131.52, and I've been using it for about 2 years now.