I need to start off by saying that I rarely post anything on here but have been reading the posts on here for many years and get great enjoyment from it.
I am a little late to the party on this topic but I do have a few random thoughts. I am a not a professional welder, but I do teach some welding in a vocational setting, so here are a few.
One option for gas bottles is that some suppliers now offer I lifetime lease. I have switched all my bottles that I used to rent at the school over to this option. It was actually cheaper than purchasing most of the bottles outright and there is no certification that you have to deal with. When I need a bottle filled I can either exchange it at a local company if I am desperate or the supplier delivers weekly at no charge.
With welders there is no substitute for power, however every welder is different. I have 3 of the exact same lincoln stick welders and they all weld differently, I also have 2 Miller MIG welders exact same machine but the settings you use for the same stock is different. I have one of the three stick welders that I use and 1 of the MIG welders that I use exclusively when I am welding because It is familiar to me. I think we all like what we have because we are comfortable with it.
I think that flux core wire feed is garbage, I have not had much success with it. Maybe some have, and maybe my problem is It doesn't work for me because I am used to gas.
I have not really noticed any difference with the type of gas you use when welding steel. But I do believe that gas flow is extremely important to help prevent porosity and oxidation. Also how well you prep the metal makes a huge difference in the quality.
Lastly, a lot of people talk about TIG welding, and I know several people that own them and they sit in the corner unused. I don't actually know anyone who is a good TIG welder. I can TIG weld but I am not good at, Eventually I will get a nice weld on aluminum and stainless, but I have to practice a lot on scrap to get it set up right. There is just a lot to know for each metal, polarities, AC/DC, Prepping the Metal, Which Tungsten electrodes to use for which metals, How to properly grind the electrodes, Using separate grinding wheels, and stocking all the right rods for different materials. Can get expensive too. I wish it was like MIG 5 minutes to learn the operation, and a little practice and you can weld most of the things that you need.
Ok, Lastly again- Welding is very individual lots of room for individual technique. I teach the progression from MIG to Stick to Oxy-Acet to TIG. Sometimes people rag on me for teaching oxy or even stick saying that they are outdated, but the motor skills learned from one to the next are really helpful by the time you get to TIG. Plus who in there right mind does not want to have a torch in their hand