Love my dump trailer. Worth the $ if you can utilize it enough to justify the cost .
Dump trailers are a beautiful thing, but you need a pretty serious tow vehicle, to make a dump trailer the most practical move. Their payload to GTWR is so low, by comparison to less complex trailers, that it's a tough sell as a firewood hauler or general purpose wagon. Also, the load-in height is high, so their advantage there falls short for anyone who doesn't also have a front end loader on site while loading. Add to that that it's no fun getting tractors in and out of of them, the high COG, and they really become a better "second trailer" option for someone who already has a landscape or utility trailer.
But, to the OP, I was going to say "trailer", before even reading his post. Bholler and wishlist bring up a good point, if you're getting wood out of "extreme" locations, but for me that wouldn't outweigh the other advantages. Also, I'd bet I could get the little 5x8 utility trailer in the OP's question in and out of almost anywhere most folks could get a truck, with likely too few exceptions to really kill the deal for me.
I have both, but almost always take the trailer when fetching wood. I can list some reasons, to help you decide which is for you:
1. Wood is heavy. Wood hauling vehicles nearly always run out of payload capacity, long before they run out of space. My truck is only 1/2 ton, and squats pretty hard with 1000 lb. of wood in the bed. But my trailer has a payload around 5500 lb. You're talking about a smaller vehicle and trailer, so the numbers are different, but I'd be willing to bet the ratio is similar.
2. I put a winch on the front of the trailer, so I don't have to buck and lift rounds. Now I just drag full 15' logs right onto the trailer (16.2' box), drive home, and drag them off with the tractor. This is a heck of a lot easier than lifting rounds into a pickup, and then tossing them back out at home. You could do the same with 6' logs, or some other even multiple of your preferred split length, that's slightly shorter than your trailer box.
3. My trailer gets pretty banged up, but my truck stays (relatively) pretty. The truck I had owned prior to buying the trailer got real banged up, I bowed the tailgate out dragging a 48" diameter log out of the bed, and dropped at least one or two rounds on a rear fender in the course of moving several dozen cords of rounds over the years. I don't need a real pretty truck, but I do drive it for business and family, and don't want it to look like complete hell.
4. When you make one too many scrounging runs in a day, and run out of daylight on your last trip home, I don't mind letting 5000 lb. of wood sit in the trailer until I get home from work the following afternoon. I simply block the rear and crank up the tongue jack to take most of the weight off the suspension. I don't like leaving my truck squatting under a heavy load for a day or three, especially if I might need that truck to drive to work!
5. I put my saws and tools in the bed of the truck, and the wood in the trailer. No more accidentally crushing a saw, or trying to secure them on top of a load of firewood, and hope they're still there when you get home. Saws, chains, cant hook, my lunch and water, and other gear stays in the bed of the truck.
6. You'll find a million other uses for the trailer, if you choose one well-suited to your needs. I have tractors and mowers that I can haul with me to grounds work days at church, or if one needs to go to the dealer for service (thanks, John Deere electronics). When I needed to haul a boat trailer home from the sandblaster, and didn't want to drive it on hubs potentially full of sand, I simply put that trailer on my wood-haulin' trailer to bring it home. You could end your days of frustration, trying to blindly tow or back up a too-small log splitter, by simply putting it onto your utility trailer when you take it somewhere.
I guess there's one other, less quantifiable bonus:
7. Your neighbors, friends, coworkers will see you hauling loads of wood around town, and you'll become known as "the wood guy". Soon you will have so many offers for free wood, that you'll be turning down anything less than the most prime. Well, that happened with me, anyway.