Windows only: uTorrent is far and away the most popular BitTorrent client among Windows users, and they've recently pushed out a shiny new 2.0 release, bringing with it bug fixes, performance improvements, UDP support, automatic bandwidth regulation and more.
We explained the UDP update when uTorrent 2.0 beta came out way back in August of last year, but in a nutshell it means better performance for torrent trackers and ultimately for you, the user.
We also discussed the new transfer cap when the release candidate hit the streets, but again, simply put, it allows you to set bandwidth transfer caps to limit how much your client uploads or downloads over time to help avoid going over ISP caps.
As for uTP (which is kind of like your router's Quality of Service functionality):
uTP is an alternative communication method for BitTorrent traffic that allows the client to automatically regulate its bandwidth usage to avoid adversely impacting your internet connection. This will allow you or other users on the network to download their torrents but still allow others on the network to function with little difference. This does not require any additional setup.
In addition, uTP in this version has added its own form of STUN, a method of getting incoming connections without direct connectivity to the Internet. This allows µTorrent to punch holes through routers and firewalls to increase connectivity and improve speeds. It is even possible to connect two firewalled peers through uTP's NAT traversal feature.
In a nutshell, uTorrent 2.0 is a download any BitTorrent lover will probably want to grab in short order.
uTorrent 2.0 is a free download for Windows. The app is available for the Mac, but this 2.0 release doesn't apply. Note: Be sure to skip the Ask.com toolbar when you're installing — unless of course you want it, which you don't.