We have searched about Google feedburner and using it since many years, but know it facing many problems daily, some time subscribers decrease immediately and sometime decrease day by day. So may be you probably thinking to migrate it to other. Or may be would like to use Email list manually.
So i would like to explain, you subscribers from feedburner will not waste, you can export emails list from feedburner easily. Export it as CSV, and use it where ever you want to use. Mailchimp is also a email marketing tool online, it also allow you to import list from other.
How to Export Email List From Feedburner
Tutorial Explained well with screenshots.
Step 1 > Go to Feedburner Dashboard. and Open your Blog Feed or Account. In analyze section you can see a Link with this Text See More About Subscribers Click on it.
Step 2 >> Open Feedburner Subscription Section, then you can see Manage Subscribers List.