Main benefits:

Can link DNA tests to your tree, and get more benefit from the wonderful DNA tools on this site.

Main pitfalls:

Rather prone to people carelessly using SmartMatches without checking likey validity of the tree data / relationships

Free tree has small size limit, although you can upload larger trees using FamilyTreeBuilder for editting.

Recommendations

Check out the MyHeritage free desktop software, FamilyTreeBuilder for easier updating, and synchronising, of your tree.

Thoroughly check out all the tree and DNA settings, particularly privacy options.