I think the miller is a better welder. if you have the 230v avalable buy the miller you wont regret it.
I am a welder by trade, have been for 18 years. Both are good machines, but you will be better off with the 230v. You can get the lincoln in a 230, but miller has been building them longer, thus they might be better at it. My welder at home is the lincoln 230, I build a 50 foot extension cord and its great. 230v power will cost less money to operate, the duty cycle is better, you get better welds on heavy material (better penetration) and you can run bigger wire if you like. All in all your its worth while to run 230v, even if you have to get electrition to wire it in.