I would prefer eMule. Its has no adware, no spyware, or any ware. It has TONS of servers to choose from (many sources). Very reliable, fast, easy to use.
FOR WINDOWS XP SP2 USERS
If you are using Windows XP Service Pack 2 you MUST download this patcher. Details are on this website:
After downloading, run it and follow the directions. In eMule, go to options-->extended. In the extended settings, change the max half open connections to 50.
-->Search and download anything you want in one day... The next day, most of your downloads will be completed.
-->Set the upload speed to about one-half of your ISP's upload speed so that you can surf the web faster while using eMule.