Buying your first plasma cutter can be quite a daunting task without the necessary knowledge and such a wide variety of manufacturers and models on the market. Plasma cutters are expensive tools and purely learning from experience can turn into quite an expensive exercise. Here are some things to consider that could prevent you from buying blindly and help you to select the right plasma cutter for your purpose.
It is important to consider how regularly you will be using the plasma cutter, because the higher the amperage output of the plasma cutter - the greater the duty cycle is at lesser amperages. Most manufacturers provide the necessary duty cycle information in their manuals or product descriptions.
If you intend to use the plasma cutter very regularly, it is recommended that you purchase a larger unit than what you would need to cut the material you will be working with. Otherwise, if you plan on using the plasma cutter less frequently, consider getting a plasma cutter capable of cutting the thickest material you intend on using.
If you plan on using your plasma cutter outside of your workshop occasionally, you should consider getting a more portable plasma cutter. Portable plasma cutters are smaller and lighter, but most perform just as powerfully as the larger units. If you're going to use a portable or semi-portable plasma cutter, you might need to get some form of portable compressed air and a decent portable generator.
If you'd like to automate your plasma cutting at some point, you should select a unit that doesn't have a high-frequency starting circuit. High-frequency starting circuits use a high voltage spark to initiate the plasma process, instead of a lower voltage pilot arc. High voltage sparks can cause electrical interference that might affect or damage other electrical or electronic equipment.
Plasma cutters are quite expensive tools which make it even more tempting to opt for a cheaper imported unit. But a cheaper plasma cutter might cost you more money in the long run if the cost of replacement parts and consumables are taken into account. And an inexpensive machine that doesn't meet your needs is a waste of money. Don't choose a plasma cutter unit solely based on cost, find a plasma cutter that will fulfil the purpose you have for it efficiently.