Another vote for Eternabond here. I've even heard of folks stop using caulk on their roof in favor of Eternabond at all seams. But even it has it's limits. It was used from the factory on the seam between the roof and the end caps. Not knowing what I was doing, I caulked a few small cracks in the tape. Well of course new cracks formed. I ended up removing all the original Eternabond and Dicor and replaced all with new. It's holding up really well after two years.
As for the horizontal Dicor, I too had disappointing results. It shrunk and separated after about three years and allowed more water intrusion along the forward side seams of the fiberglass.
In the end, I highly recommend frequent inspections of all seams, roof and sides. Especially if your rig is wooden framed walls. Mine is aluminum studs, and so far the only damage has been surface rusting of the front frame pieces.
Safe travels, y'all
P.S. Never put Eternabond or any other sealant on top of new caulk. The caulk gives off gases as it cures and will form bubbles under the tape. OK to caulk over tape, but be aware if the tape is cracking, it will continue to deteriorate. Best to remove and replace.
