Do your own research on the clients you use but these are generally the most widely accepted clients. Keep in mind that some clients (such as newer versions of uTorrent and BitTorrent) have been known to be bundled with crypto miners and adware.
Torrenting itself isn't illegal. However, sharing and downloading copyrighted material may be illegal depending on your local laws. Copyright organizations can send takedown notices to the internet service provider (ISP) of the file transfer participants and start lawsuits against them for infringement.
|Wide range of quality (audio and video-wise)||Often heavily compressed (to reduce storage/bandwidth costs)|
|High quality fansubs||Official subs may be bad|
|Downloaded files are kept locally permanently||Accessibility relies on internet connection|
|Guaranteed ad-free experience||Not always ad-free|
|Stable internet connection is not required||Requires a stable internet connection to avoid buffering while streaming|
|VPN is needed in some countries||VPN is not required|
|Takes up local storage||No storage is used|
Erai-raws upload currently airing anime.
HorribleSubs formerly uploaded airing anime.
However, they're not the best source for older anime or anime that has been released to Blu-ray. For the absolute best video quality or the best fansubs, try searching for the releases mentioned in:
Check out the sourcing guide for more detailed information on finding the best release for any particular anime.