Rws, what are your welding requirements? This will help you determine the machine (ignoring cost for the moment).
That 1st link is for a flux core welder (if I read it right). You will have to get different drive rolls for solid core wire (if that box supports that mode?.
That 2nd machine only goes to 88 amps. Good for sheetmetal only (IMHO).
If you are going to weld on anything that 'goes on the highway' you can't just lay booger welds on top of each other. Too much liability.
Thick steel requires amperage. You are just kidding yourself if you have to do multiple passes on 1/4" plate. Wouldn't trust it no how, no way.
You are going to have to pay more the higher the amperage rating and the higher the duty cycle. Duty cycle goes down as welding current goes up (on any given welder). Flux core welding tends to spatter more. That can be a consideration (it is for me).
So decide what you want to potentially weld and go from there.
Sheetmetal, what gauge range?
Angle/bar/plate 1/8" to what thickness?
Welding things your life depends on (car frame, trailers, gantry crane, something to hold a few thousand pounds)?
Gas vs gasless (flux core)
Ever going to consider aluminum (big buck upgrade in price to do it).
Duty cycle? 80%+ when doing sheetmetal is ok. Push the same welder to do 1/8" or thicker and if the duty cycle drops to 10-20% that is going to really suck.
If you are on a limited budget then probably the best bang for the buck is the Hobart line. They are basically downsized (quality/component wise) Miller welders (probably come off the same production lines). Look at the Hobart handler 140 for about $600-700.
Your next challenge is how are you going to cut whatever you are going to weld together? More $ and more decisions.