Some owners have reported that the round bars work better if the coupler is on the top and trunnion is better if coupler is on the bottom. Some say the ride with round bars is noticeably better because they claim there is more spring in the round bar. I believe the round bars only go up to 1,200 lbs while the trunnion one go higher so if you have a heavy trailer, you may need to go with the trunnion type anyway or if you plan to upgrade to a heavier TT in the future.
We recently bought the dual cam setup with trunnion bars. I like it a lot. The initial setup took a lot of fiddling and playing around, but that might have just been me. It's really important to find a flat and level spot to park on and do the setup. The last step should be a trip to the scales to ensure you are transferring weight in the correct amounts. Our last WDH was a plain jane round bar one (no dual cams). I found it a little more awkward to get the end up of the bars into their "sockets" as you kinda have to lift upward at the end. We lost one of the little spring retainers once so we bought some spares just in case. Still trying to get used to the weird popping, groaning and creaking noises when turning and backing up. People look at you like the back end of your truck just broke and fell off.
I do like the feel of the trunnion bars when lifting and handling them into place. They are evenly balanced front to back, unlike the round bars. A little easier to store, but I can't rest them on the A-frame like with the round ones. You need to keep the trunnion end off the ground to prevent sand and dirt from sticking on it. I make sure the trunnion bar is sitting on a wood block or lego block. The wood block under our tongue jack works well for this.
Another little thing - it helps to keep the cams lubed where they contact the bars. Reese says to use vaseline only. I read the other day about someone using graphite powder in an aerosol can. I might try that as it is more convenient.
Lots of good tidbits of info. in these threads from the Forest River forums:
Some Strait-line questions... - Forest River Forums
Newb WDH and Sway control questions - Forest River Forums
Tow Vehicle Question - Page 2 - Forest River Forums
There's more on this forum but I can't look for and post them all so you can always visit them.
After searching all over the internet, I found the best price was on Ebay at $450 (with free shipping). I read recently where someone said Reese is moving their production to Mexico but the dual cams on ours are stamped *made in China"..... Maybe some parts like the bars are made in the US?