witch is better to use ?

[dindangdu at yahoo.com (aaaaa bbbbb)]

Hi, i'm new in this metasploit scene and would like to know witch version of metasploit is better to use at this time  
2.3 or 3 version of framework ? 

And i am getting error on framework3 when typing in irb shell: help

NoMethodError: undefined method `execute' for IRB::ExtendCommand::Help:Module
        from (eval):3:in `irb_help'
        from (eval):9:in `send'
        from (eval):9:in `help'
        from (irb):1:in `cmd_irb'
        from ./lib/msf/ui/console/command_dispatcher/core.rb:186:in `cmd_irb'
        from ./lib/rex/ui/text/dispatcher_shell.rb:229:in `send'
        from ./lib/rex/ui/text/dispatcher_shell.rb:229:in `run_command'
        from ./lib/rex/ui/text/dispatcher_shell.rb:196:in `run_single'
        from ./lib/rex/ui/text/dispatcher_shell.rb:191:in `each'
        from ./lib/rex/ui/text/dispatcher_shell.rb:191:in `run_single'
        from ./lib/rex/ui/text/shell.rb:118:in `run'
        from ./msfconsole:63

I installed irb but it didn't fix this problem, how can i solve it ?