Hi Harshitha,

Changesets are a way to deploy components through the standard salesforce UI. A user first creates a Outbound Changeset on the Source org and adds the components they wish to deploy. Once ready, the changes is uploaded to a Destination ORG. The deployment can then be validated and deployed from within the Destination ORG>

-Packages: In the packages you can deploy the metatdata across the orgnizations.
You don't need access/ deployment connections with the other org. So when you need to deploy the metadata to many orgs, in that case we use packages.

    -Managed Packages: The components will be locked i.e. you cannot change. Aslo upgrades to the components will be availablle.

   -Unmanaged Package: You can edit the components of the package. Unmanaged package will not have upgrades.

 
1. Ant also doesn't "track deployments". But, deployments are listed in the Setup > Monitoring > Deployments area.

2. You can clone a project just as you can clone a change set. They're just files on your computer. Plus, you don't need to clone just because you've made one deployment (like Change Set, which locks it after an upload).

3. Ant and Eclipse both use security tokens, but only outside the trusted network. This is usually a non-issue for people that work in offices, because they have static IP ranges they can list to nullify this requirement.

4. You can move change sets between any sandbox for an organization (if you have multiple), and/or production.

5. Eclipse can't push code without coverage to production environments. You can never, ever break this cardinal rule, no matter how you deploy. Sandboxes and developer editions do not require testing or coverage, however.

Hope this helps you!
Best Regards,
Jyothsna