Suggestions on which welder

[drthunder33]

Super happy with my Powerplasma 60s and now it's time to retire the old ac buzz box.

I've been all over the map looking the pa140st, pa160sth, pa200st and even the awesome pa300 (is this an "ST"?) and aside of just buying the biggest one I'm still a little unsure about which one.

A little specifics so maybe you can help.

I will be welding mild steel up to 1/2"
Mostly repairs and fabrication on my mud trucks ranging from frame work axle brackets suspension components and wheel centers.
I have about 75lbs of 1/8" 7018 in sealed cans
I don't currently tig but it would be nice for thin sheet and clean welds down the road
input power is not an issue, I have plenty
not doing production. probably wont get used more than a couple of times a month
Cost is a factor but not the ONLY one.

I've read all the technical specs on the site and it appears that any of the above will work (I know, more power = better) but I'd like some opinions.

Thanks