Richard Shea an attorney in Connecticut who publishes the Connecticut Estate Planning & Elder Law Blog has a good description of each and the differences in an article titled Power of Attorney v Conservatorship.
He summarizes the differences by stating:
A power of attorney is a relatively low cost and private way to decide which family member or trusted friend will have the legal authority to carry out your wishes if you can no longer speak or act for yourself. If you do not have a power or attorney or if your power of attorney is not drafted properly, and something happens that results in your inability to make decisions, your family/friends may later face court proceedings and court supervised Conservatorship. A court proceeding is not only costly, but the person appointed as your Conservator may not be the person whom you would have chosen yourself. And, as stated above, not having a properly drafted power of attorney could significantly limit financial and/or Medicaid planning that could be done on behalf of the principal.
Another significant difference that I often emphasize with my clients is that although a Durable Power of Attorney allows you to act when and if you want to, a Guardianship makes you legally responsible to act.
You should discuss your specific plans for a Florida Durable Power of Attorney or a Florida Guardianship with your Florida Estate Planning Lawyer to determine which is the right vehicle for your needs.