GoSign has several advantages over the built in FileMaker Signature Capture. Here is a comparison chart.

Built-InGoSign
Capture signaturesYESYES
Store signatures in container fieldsYESYES
Store signatures as base64 encoded stringsNOYES
Display “Terms and Conditions” on the same screen as the signatureNOYES
Control access with scriptsNOYES
Stop users from using picturesNOYES
Place signature capture anywhere on layoutNOYES
Control base line thicknessNOYES
Control base line colorNOYES
Control signature pen thicknessNOYES
Control signature pen colorNOYES
Optionally capture signature base lineNOYES