So here is what I suggest, find a quilting friend to go with you, and book the machine together, That way you have help especially for loading and if you forget anything, it would be faster to spitball with someone else that standing there scratching your head.
I have done both, and with my physical capabilities anything over a twin pretty much would get tied or SID, which for some are okay, but having the use of the long arm has opened up a whole new ball of wax, and I save a lot of time doing it on the big one, no more sandwiching it (which I have a hard time finding the space to do especially with the animals around)
My mom came for a visit last summer and from what she saw of the machine to start with she thought it was a lot of work, she then helped load a couple and did the quilting on one of them, which was pretty funny to watch, she did a good job on it even though at the time she was using the machine she thought it was going to be so much worse, and after it she said if she was closer I wouldn't have to quilt anything ever again.
So for cost and time wise, things to consider, how would you do the quilt either way, and the different looks that they would give. which one will you be more happy with?
Cost of the quilting machine compared to how many quilts that you would be doing on it, it is a big lay out for the machine (not that everyone is buying one) to only do one or even two a month, so really is it that expensive to rent one? plus the space it takes up,
Time wise, which will take you longer?
If you were all closer I could give you a better deal to use mine, but I am also m=not trying to make a living at it,