Right now I'm trying to decide whether I'd rather have, and get more use, from a trailer or a roof rack. There are compelling reasons behind both but I think I'd really just like to buy one and be done.
I had a roof rack on my last TJ. I had it specifically to carry my kayaks, but also used it for other things.
IMHO:
- Roof racks on Jeeps are unbelievably loud at anything over 30 mph. Some are quieter than others, and you can do some things to mitigate the wind noise, but the noise level will be significantly elevated over no roof rack. Over the course of a long trip, it can really wear you down and be very uncomfortable.
- Capacity and center of gravity: Even the strongest roof racks don't carry much weight. You also don't want to put a ton of weight up there as they significantly raise the center of gravity of your vehicle.
- Load height: no contest between a roof rack and a trailer. Trailer wins hands down and for this reason you can also carry a much larger variation of things in the trailer. Also, unless you have a REALLY high garage door opening, you're going to be loading the roof rack outside. That's a PITA on a hot or a rainy day. A trailer can be loaded in the garage.
- Hard to remove the top with a roof rack. Some roof racks make it impossible. Even with the easiest to use roof racks, it turns a 30 sec. operation to flip the Sunrider back into a minimum 10 minute operation.
- Cost: In the short term, roof rack wins. If you want the cheapest option to carry more stuff, even the most expensive roof racks are going to be cheaper than a GOOD trailer, even if you're building or restoring it yourself. In the long term, the trailer probably wins. You only need to buy one trailer. If you get a new model Jeep, it's going to need a different roof rack.
- Longevity and versatility: Trailer wins. You can pull the trailer behind all of your other vehicles, lend it to friends, etc. When you replace your Jeep with a different one, the trailer hooks right up to it. If you take care of the trailer, it can last for many decades. With a new model vehicle, you'll need a different roof rack.
- Turning and backing up, parking lots, etc.: Roof rack absolutely blows away the trailer here. A trailer is going to make your Jeep really long, even a m416 style trailer significantly increases the length. Backing up a short trailer... takes... practice. Backing one up on the trail or other small spaces... takes... more practice.
All that said, there are places for both. Roof racks have significant downsides but I used the heck out of the one I had. It more than paid for itself.