Never used one myself but I do know they are becoming a popular brand in Europe among the inverter type TIG machines. From what I have seen on them they run right up there with ESAB as far as quality of weld. The parent company is based in Finland.
I bought one used from a machine tool dealers private stash in his basement. It is a Kempotig AC-DC 250. It was a sweet little tig welder for 4 years then it bit the dust on me. Have had it to three different weld shops and struck out on all of them. Kemmpi is real quick to respond to my emaails but they are several thousand miles from Pennsylvania. But if I could get it fixed I would certainly invest the money. I wish thy would come back to the states they are great machines for sure.