Portability and power supply matter as much as the process itself. A stick welder will run from a generator or a domestic supply in places a gas bottle can't easily follow, while MIG and TIG set-ups need a gas cylinder and, for anything beyond light-gauge work, a heavier electrical supply. Workshop layout, the materials you weld most often, and how frequently the machine needs to travel are all worth weighing up before settling on one process.
Space and power supply are the other two practical constraints worth checking early. Confirming that a chosen machine will run comfortably from the electrical supply actually available in the workshop, and that there's room to work safely around it with materials laid out, avoids the common mistake of buying a machine that then can't be used the way it was intended.
Matching duty cycle to actual workload, rather than just chasing the highest amperage figure, is the difference between a machine that keeps up with the job and one that keeps tripping out halfway through it, and it's a question worth raising with a supplier before you buy, such as https://stayzada.com/bbs/board.php?bo_table=free&wr_id=928463.
For anyone starting out, talking through process, budget and set-up with people who deal with first-time buyers regularly is generally worth more than another hour of reading spec sheets, and that's exactly the sort of conversation the advice line at https://stayzada.com/bbs/board.php?bo_table=free&wr_id=928463 is there for.
The abrasive material itself matters as much as the shape. Discs formulated for steel typically contain aluminium oxide, while stainless steel usually calls for an inox-rated disc that's free from iron, sulphur and chlorine contaminants that could otherwise cause surface corrosion on the stainless. Aluminium and other soft, non-ferrous metals need their own dedicated abrasives too, since standard steel discs tend to clog quickly and produce a poor finish on softer materials.
Buying a first welder is easy to overthink. Rather than starting from a shortlist of machines, it helps to start from the work: what materials, what thickness, and how much of it will be done indoors versus outside or on-site. That single question narrows the choice between MIG, TIG and MMA far more usefully than comparing spec sheets in isolation, whether you end up looking at a Jasic entry-level MIG package or something further up the range.