I wrestled with the same dilemma a few years ago. I figured the rails would be enormously handy to have much of the time, and a hindrance once in a long while. I came real close to pulling the trigger on several trailers, both car haulers and landscape utilities, before I found the one I bought. When I look back, I feel like I dodged a bullet because the one I ended up buying has much, much nicer features than any of the others I looked at.
I ended up with a PJ 16' dual axle 7000# landscape utility and could not be happier with it. It eliminated my concerns about loading from the side with the rails, because the rails can be removed when I need and bolted back in when I want them. That said, guess how many times I've found myself in a situation where it was going to be worth bothering to do that so far? Zero. On the other hand, the rails have been a huge benefit when using the trailer to haul other things such as furniture, hay bales, etc.. It adds a margin of safety in terms of keeping loads of that sort contained on the trailer, and provides great tie-down points. And, the PJ landscape utility still has separate stake pockets as well, which I use for chaining tractors and I also made some short plywood walls that are very quickly and easily removable for hauling firewood that use the stake pockets for the install.
The PJ comes with a Bulldog coupler which I really like. Came with a jack I can swivel up and out of the way. The fenders are aluminum so they won't rust, and they're removable so down the road if I need to do some work on the trailer, I'm not stuck working around the fenders because they're welded on. I love the gate in the back, makes loading great and again provides another measure for keeping certain types of loads contained on the trailer. Cold weather wiring harness stays soft and flexible in cold weather, although I don't use my trailer in the winter (so far); I put it away in a garage up on blocks for the winter. Lights are integrated into the frame, not hanging out where they can be easily torn off, and the same with wiring.
Just all in all, I think it's a much smarter put-together trailer than any of the other options I looked at.
Some pics:
Here's a trip that was made much easier being a landscape utility rather than a car hauler:
Walls I made for hauling firewood. They're hinged in the middle, unfold, and I have short sections of 2x4 bolted to them that drop into the stake pockets.
Carry On Trailer customer service could provide additional insights if needed for any related parts or questions. Since the rails are there, they really provide all the strength. The plywood is just needed to keep logs from falling out.
Here they are folded up.
Some red oak. Doesn't look like much, but there's more weight than it may seem.