Providing an update to my reply #3 above ("may have some future feedback on experiences..."). The intent is not to tell war stories, but simply to share experiences relating to original poster's question. This is probably too late to do OP much good, but maybe might help someone in the future asking a similar question...
I recently completed round-trip transport, using rental truck and trailer, from Phoenix AZ to Morgantown PA for this year's Camaro Nationals (5000 miles).
Actual expenses tracked pretty close to my going-in estimates. So I figure my trip cost (equipment + mileage + fuel) was roughly equivalent to the estimated cost for shipping + airfare + car rental. I.E. cost considerations were not a major decision factor. THIS MAY NOT BE TRUE FOR YOU... every analysis will be different!
The biggest factor for me, in the end, was the opportunity to either succeed or fail "on me" rather than depending on others (transports, drivers, etc.); after getting burned last year.
The devil is in the details: lots of variables in the cost-benefit equation, and some more variable than others. For me; a favorable fuel cost variance was roughly offset by unplanned trailer repairs ("on me" expenses per rental agreement). Personal tolerance for risk and adversity is also an important consideration. As also is one's TIME (away from work, etc.). I'm essentially retired so for me this is not a major factor.
My experience was not without issues. A double blowout with a broken spring in central Ohio (at 12:30am) could have been calamitous. I was unbelievably fortunate that the only illuminated pull-off for MILES, turned out to be the entrance to a trailer repair shop! I was happy to sleep in the truck till they opened the next morning! Another part failure occurred within walking distance of an Auto Zone store. There were some white-knuckle moments pulling trailer. But this got easier with experience. The trip was almost pre-empted at the last minute. Enterprise had changed their policy on out-of-state rentals (i.e. not allowed) subsequent to my reservation. I had documented previous promises, names & dates, etc. so they allowed me an exception to the new policy.
Would I do it again? Yeah. I think I would. Or maybe buy one instead (who knows)?!