Look at the sellers return and support policies carefully. If they require sending it back to China for service it will take a long time and have high shipping costs.
Some sellers do their own service and specify quality components used (no used parts or counterfeit ones.)
Its also worth considering what you would like to do with the unit. Are you a hobby/DIY welder or would you be planning to use the machine for industrial/money making purposes.
Its worth considering this because if the unit is somthing that will be a tool for making money and supporting your business, then it might be worth investing a little more. However if your only going to be using it at home for diy projects etc then its not so critical.
As Shenion said, they can be hit and miss but important its got local support.
I realise this is an old thread, but its the newest i can find on the subject....
I was tempted in by the price of a 180a Rilon tig/mma inverter.
A quick check on the spec and it`s rated at 20a input.
Not a huge problem as I already had a 16a socket, protected by a 25a mcb installed in the shed for my mig unit.
A look at the cable revealed it to be 6mm2 so would take 36a (encased in conduit), plenty enough for the welder. A quick trip to the electrical wholesalers had me upgrade my 16a socket to a 32a one, and a nice new 32a plug fitted on the welder.
Assemble the torch, attach the gas hose, fix the earth clamp to the workpiece, minimum amps (10) selected, and we are ready.
Turn the unit on, press the trigger....arc.....BANG.
The welder tripped and so did my 25a mcb
Hmmm, reset mcb, welder will not turn on, sparks flying from on/off switch.
To be fair, the supplier sent me a new unit next day......
Exactly the same scenario....
Both units now returned and I expect a full refund.
I will not be buying Chinese welders again!