There isn't a really big difference between them. Version 2 is
somewhat more detailed and uses different symbols than Version 1 to
represent the measurements of Latency, History and Uptime. Here's a
typical Version 1 stats format
<http://mixmaster.shinn.net/stats/remailer-list.html> and here's a
typical Version 2 <http://www.neuropa.net/%7Egretchen/rlist2.html> .
These are in HTML.  You may also download TXT versions of each.  The
file names may vary (rlist, rlist.txt, remailer-list, etc...), but
here are the recommended file names:

Filename   Remailer-Type Format   Stats-Version 
rlist           Cypherpunk      Plain Text      1 
rlist.html      Cypherpunk      HTML            1 
rlist2          Cypherpunk      Plain Text      2 
rlist2.html     Cypherpunk      HTML            2 
mlist           Mixmaster       Plain Text      1 
mlist.html      Mixmaster       HTML            1 
mlist2          Mixmaster       Plain Text      2 
mlist2.html     Mixmaster       HTML            2 

Further information on stats formats comes from RProcess'
Specification and RFC for Remailer Stats Version: 2.b
<http://www.skuz.net/potatoware/PSKB-032.html>.  Most users need only
consider which stats version their client will read.  Here is a
summary of the recommended version.  Further comments are below.

Software	Recommended Version	Recommended Format
JBN1			1			HTML
JBN2			2			Plain Text
Mixmaster		1			HTML?
Quicksilver		1			Plain Text
Private Idaho		1			HTML
Reliable		2			HTML

Jack B. Nymble v.2 and Reliable v.1.0.5
JBN2 and Reliable 1.0.5 can read both types of stats.  Pick a format
that you like and stick with it.

Quicksilver
Quicksilver reads only Version 1 stats in TXT format (e.g., mlist.txt
and rlist.txt).

Mixmaster
The operator of Cmeclax Remailer, <cmeclax@ixazon.dynip.com>, confirms
that, as far as he can tell, "...Mixmaster 2.9 doesn't understand
Version 2 [stats]. I tried it a while ago, and it had no reliability
data when I made chains."

Jack B. Nymble v.1
Frog-Admin says that JBN1 only reads version 1 stats.  In that
operator's experience, JBN1 works better with HTML files
than with plain text files.

Private Idaho
As for Private Idaho, there are lots of different variations of this
older program. But it's safe to assume that most of them require
Version 1 stats in HTML format (e.g., remailer.htm) and won't work
with Version 2.

Other Clients
Be aware that some of the older client software like Potato, Decrypt
and Mixmaster 2.0.4 cannot read Version 2 Stats.