I have one, your right its dc only, but it does have hf start, supposedly you can weld ally with these, but I've only used mine in steel, you need to tighten all the connections internally, they are not built that well.
I also have a 200 amp mig, thats still working 4 years on, the tig and mig are inverter.
There is a ac version, its about 200 quid and has a load of controls, I wouldnt mind pulse and clean cycles.
There is a saying though you gets waht you pays for, yours is gonna take grinding dust & abuse for a long time, I worry every time I put te grinder near mine, the 320v bus is gonna go bang one of these days.