Can you get 220 out there at all? That will really open up some capabilities. Trying to do much of anything aluminum with a 115 volt machine is probably more of an exercise in futility than anything else. It will kinda sorta work on certain things, but once you get the opportunity to try both, you'll understand the difference.
Also, a 115 volt machine is going to be somewhat limiting on thicker steel. For light tubing and all, it would be fine, but realistically you aren't going to get much more than 1/8 steel out of most 115 volt machines, running solid wire and shielding gas (flux core will get you above that, but who wants to run that stuff in the shop - it is an excellent process, and has it's purpose, but for in the shop work, it isn't necessarily ideal). Sure the machines claim on the box the capabilities, but when you start looking at the fine print (that isn't necessarily included in the box), you'll see the conditions at which these test welds were done. Let's just say they aren't normal operating conditions. You wanna have a little fun, start emailing Lincoln and Miller about that. If they respond, the answers they give answer every question but the one asked.
If you could get 230 voltage, something like the Millermatic 211 is an excellent machine. Has 115 and 230 volt capabilities (115 at a lower output rating), direct hook up to a decent spoolgun, pretty decent power size, etc. I think the Hobart 210 series (could be 210, or 211, don't remember) is probably a similar machine, with a lower price tag. I would imagine it would be fine for hobby use.