Sealing Maintenance

Any caulking/sealant/tape is as good as the surface preparation done BEFORE it was applied. Eternabond is a great product, if the surface was clean for it to adhere properly. Dicor is also a fine product if the surface is spotless so that it will not start to come loose at the edges. Clear urethane caulking is great for some vertical surfaces on a painted coach, as long as all of the surfaces are clean and wiped down with a solvent first to remove any wax or other contaminants. I like to keep away from silicone products since there are other materials out there that will last as long and not contaminate your surfaces with silicones that are difficult to remove if you need to do any painting.
There are many fine products out there that will perform well on your RV as long as you spend a lot of time on your surface preparation. Going over an old tape joint may or may not produce good results since you cannot clean the old surface as well as if the old tape/sealant was not there. I recommend taking off all of the old tape, to see if there were any failures in the seal, cleaning the surfaces, and applying new tape. They make a small, one inch wide roller for wall paper seams, that works great for making sure that the tape is properly adhered to the clean surface. If you do it right and take your time, you should be able to get many years of service out of all of the high quality tapes, sealants, and caulks.