IF all you ever intend on welding is sheetmetal, the 115 V welders will do fine..... But the majority of people I know that got one ended up getting a bigger one anyway when they got some experience in welding and discovered all the other things they could do with a bigger welder.... Personally, I'd rather have a bigger welder with the capability of doing the sheetmetal work with smaller wire, then have a small welder that I wish could do the bigger stuff....

Also when your looking at welders consider the duty cycle. Some will say the small welder will do frames and suspension just fine, but when welding the bigger material it doesn't take long to exceed the duty cycle of the welder. As others said, if you do go with the 115 V welder get the gas bottle and regulator, the flux core wire IMO is junk for any kind of work.

As Dart mentioned, whatever you get practice, practice, practice..... Even with the automatic settings your first welds are not going to be good ones. It takes practice to develop a technique and be able to see what the welder and the metal is doing! The quality of the weld has much more to do with the skill of the man doing it then the equipment he's using.....