Okay.  I'm gonna chime in here since I'm seeing a lot of viewpoints that I
think are pretty idiotic, IMHO.  I would like to analyze each pokemon in this
arguement and then show why each one is good and bad, and which one is better:
 
 
HP:  Farfetch'd's 50 vs Scyther's 70
Advantage: Scyther
 
Attacks:  Farfetch'd and Scyther both have the same "3 for 30" attack, so it's
even there.  Farfetch'd has a 
50/50 shot at 30 damage once.  It's quick, but a one shot deal.  Scyther has
Sword Dance, which can delay an extra 30 damage and dish it the next turn. 
Once you get to 3, though, using Sword Dance is mostly worthless except for
rare instances involving Gust of Wind.  It's a colored attack, and delays a
turn, so a slight edge goes to Farfetvh'd
Advantage:  Farfetch'd (barely)
 
Resistance: same (fighting)
Advantage: none
 
Weakness: Area Dependant.  Farfetch'd has electric and Scyther has Fire. 
Electric CAN do 40 for 2 energy vs a max of 30 for Fire at 2 energy.  Plus,
Electric is more prominant in the tournament scene right now.  This is slightly
metagame dependant, but will be pretty much the same for most people.
Advantage: Scyther
 
Retreat Cost:  Farfetch'd - 1, Scyther - 0.  This is HUGE in the current
environment
Advantage: Scyther
 
Availability:  Who cares?  You're gonna play with the best if you have it, and
play 2nd best if you don't have the best
Advantage: Who Cares?!?!
 
Splashability:  Both primary attacks are colorless and go in either deck.  A
low energy deck, though, can better run Scyther with no retreat cost.  He
genuinely goes in any deck in the environement right now.  The same is close
for Farfetch'd, but with SO MUCH ER out there, paying even 1 for a retreat can
be a pain.
Advantage: Scyther (barely)
 
    Now you're not gonna find a bigger Farfetch'd fan.  Heck, my first article
ever over Pokemon was a single-card strategy written back in April over why
Farfetch'd was the Pokemon that goes in every deck.  He's been replaced
unfortunately.  
    Concluding, Scyther is superior.  Get them if you can.  Play them in 99%
(maybe 100%) of every deck you make.  If you can't get them, use Farfetch'd
because he is a GREAT replacement!
 
My two cents....
 
Scott Gerhardt
scott@gerhardt.cx