Be cautious about the Century units.  I have heard reports of them 
developing 'bird nests' in the wire spool and frustrating service.  
but the price IS attractive.

if you are a craftsman/woman and will be using it alot, i would save 
for a Lincoln or similar unit.  I would suggest the highest amperage 
unit that can run on 110v.  this gives you extreme portability for 
taking to other peoples homes and making them indebted to you.  the 
"Weld Pac" units in the Lincoln line are their bottom line and i 
would go up a few steps, tho their cost almost approaches the 
Century's at certain stores/sales.  In contrast, i have heard only 
very positive reports from people actually using the upper-end 
Lincoln machines.

If you are a discriminating sort, this advice should put you in a
dilemma.  I too was watered up for the Century units sold at Sams
etc.  Dug deeper information-wise and THEN wanted the Lincoln.  Dug
even DEEPER and bought a Miller ac/dc stick welder.  Still want the
Lincoln MIG unit and maybe should've bought that in retrospect for 
the bulk of the type of welding i do.  BUT sometimes there's just no 
substitute for amperage, gobs of it.

-dan (whose goal in life is to have gas, mig, and stick welders)