I agree that version 4 is less troublesome than version 5. However, version 5 has better e-mail enhancements.
Version 6, may be off topic for an "Oldversion" message board. BUT:
I'm not sure that version 6 has been "officially" released yet, so use with caution, it may not be ready for prime time yet. I had to look very hard to find a direct link on the Juno website.
Having said that:
http://dl.juno.com/pub/juno/quickstart/juno.exe
I haven't installed it yet, but rumors indicate that it's very similar to Netzero, they've even opened the POP/SMTP servers to third party e-mail software. E-mail setup instructions are at:
http://www.juno.com/support/email/email_setup.html
Note: The SMTP is blocked unless you are using a Juno or Netzero connection (I have Juno mail working with Outlook Express).