Miller and the Hobart brand are both owned by ITW. When Hobart was acquired by them in the mid 90s, (not sure on an exact date IIRC anyways) ITW took the light industrial/homeowner part of the company and Thermal Dynamics, the heavy industrial part. This is why a number of offerings with both the Hobart and Thermal Dynamics branding looked identical. Sanrex manufactured the inverter machines for TD then and were the first to develop the waveshape technology currently offered by Miller and Lincoln on their flagship TIG inverter machines (soft square, adv square, triangle wave). The acquisition of Miller Electric by Illinois Tool Works was in 1994 IIRC.
Contrary to what some believe, the Hobart brand of machines (manufactured by Miller Electric) are NOT exactly the same as their Miller counterparts. As was mentioned above, Hobart machines in such categories are built with lesser quality components, and often have reduced duty cycles and output ratings. This isn't to say that the Hobart line of machines are junk by a long shot. They are, however the "budget" line of machines offered by ITW, and are focused on the homeowner, hobbiest market. The Ironman MIG machines are quite well made and offer a lot of features for the money versus their Miller cousins which are much more expensive. Many of Millers and Hobarts offerings are assembled in Miller's Appleton, WI plant with globally sourced components. Since ITWs acquisition of Maxal filler metals an others, they are rebranding these products with the Hobart name as well, since it's a known and trusted brand in the welding industry. Of course, branding and marketing of such things is better left to another discussion.
As far as welding the materials for the OPs project, the key factor will be the skill level the person putting it together possesses. If he is proficient with SMAW (stick welding) then, any old Lincoln AC tombstone with 7018 AC, or 6011/6013 electrodes will do the job fine. You can buy a used one just about anywhere, and often for $100 or less. There are many options as far as larger MIG machines go, and many different brands to chose from. My one piece of advice as someone who repairs welding machines and sells them for a living would be is to put your money in something with a good resale value, and a proven customer service network (if purchasing new). On the opposite end of the spectrum, some of the import offerings aren't a bad deal for what you spend, but at the same time keep in mind that with some of them, their warranty and post sale support may leave much to be desired. If you know that going in, it makes reaching a decision much easier. There are many options as far as a used purchase goes, but again, are probably better left for another discussion being the amount of factors involved.
Good luck with your project.
IMHO of course