I've done it both ways on BaT, for varying reasons, and I totally agree with Harv, especially his opening question.
In the case where I used a reserve, on a 1965 220Seb that I had done a very limited restoration, I had a "floor" amount that I wanted which would cover my complete cost with a realistic profit. The car ended up selling for nearly 35% over reserve! While auction psychology is tough to decode, setting a bidding war aside, I would attribute a significant portion of that amount to the hours of time and effort that I put into presenting the car as transparently and honestly as I could.
Another car I sold, a 350SDL, was a driver-quality car that I needed to move out of the corral to make room for other cars. I was happy to break even on the dollar side and consider the use and enjoyment I got out of it good enough "profit". BaT wanted NR, so I went that route.
Again, this was no garage queen or concours car, by any stretch of the imagination. I had around $4k in it including the acquisition cost, and having done my due diligence I knew it would be a contentious car to sell being unfairly known as a "rod bender". I bit the bullet and went NR, while doing every possible thing I could presentation-wise to make it desirable.
I think the hammer dropped around $5k, so I was happy. The buyer was a major flake, but I was able to get past that - I thought. I got a reminder of his flakiness about 6-8 months later when I got a certified letter from the U of Maryland's Campus Parking Division with a demand notice for unpaid parking fines. Seems Mr. Flake had never put a plate on the car but was parking it all over campus without a sticker or whatever was required. They ended up getting the VIN off the car and tracking me down as the owner - also because Mr. Flake had never titled or registered the car, either!
I politely informed them that I was no longer the owner, nor had I been for some months. I also provided the contact information I had for Mr. Flake.
Dan