[Kenwood] Recommendations for 2nd HF rig

[Ed]

Fellow listers,

I'm thinking about getting a second used HF rig for use on SSB and CW.  I'd
like to have an all-mode radio that will work at least 10-80, plus WARC.  I
see lots of older used Kenwood rigs for sale at varying prices, but I'd
like to know which are held in high esteem by fellow Kenwood users.  I've
seen ads for the TS-830S, TS-850S, TS-870SAT, TS-930S/AT, TS-950SDX,
TS-940S, TS-940S/AT, TS-440, TS-450SAT.  I don't know the difference
between and S and and S/AT or if a 950 is better than a 930 or an 870
because the number is higher, etc.  I'd like to know which ones should be
avoided and  which ones are highly sought after.  Any suggestions or
opinions would be appreciated.

73,

Ed