TCPPING needs a list of hosts. This is problematic, as you don't know your IP address before the start. I suggest use elastic IPs and possibly map them to symbolic names (DNS), and then list all of the IP addresses / symbolic names in initial_hosts.
Another option is to use TCPGOSSIP with an external GossipRouter.
S3_PING is actually quite stable, and I'd recommend it if you run on EC2.
I have a presentation on this, google for it (JUDCon 2010 in Berlin) or send me an email (belaban at yahoo dot com) and I can send it to you.