I was just over at a pretty good music store looking at acoustic 12-string guitars.
You can rent them for like 5 bucks a day, $22 per month. That's nothing. Can't really go wrong at that price. Very limited selection though.
I picked up the guitars and could see no appreciable superiority over my guitar. In fact my impression: they were inferior.
But then again I picked up a $2000 guitar (not available for rental) and it really didn't stand out as that much better either.
The problem is the noise and clatter in the store. I really need the whole store to myself to just let loose like I need to and get a good feeling for what I am hearing and how things compare.
Bottom line though, unless I get repeated feedback that people are not liking the sound of my guitar in the recordings, I'll probably just stick with that.
My guitar, old though it may be, is probably a pretty good guitar.