Tig welder invertor or transformer type ????

[autofetish]

My very nice tig welders keeps having issues

I'm now on my 3rd trip to the repair shop and I'm just about the get a quote for a new HF unit.

I'm lossing faith and just don't trust it. As I'm learning I need to be sure the welder is fine and I'm the problem.

I'm thinking about cutting my losses and buy a new tig welder

I have 240v and a 3phaze 3kw convertor ( so should stick to a 240v unit )

I will be welding stainless and Alu so need acdc

I don't care about small and portable as its workshop based

So new invertor type or older transformer type

No ting tong crap

Advice ?