We're using SocketTools with PB 12.5 with no problems.
You'll need to set the following properties for a secure connection to gmail:
Secure = True
SecureProtocol = 8 // stProtocolTLS1
RemotePort = 993
RemoteHost = "imap.gmail.com"
We've been using SocketTools SMTP object for years, sending mail through gmail and other hosts, with no problems. We also use other SockeTools objects as well. They seem to be pretty solidly written.
I just modified our SMTP code to use IMAP instead and got a successful connection to gmail, so it does work.