I don't know what the "best" is but I have the Utopia and it helps significantly. I have not tried any other ones. I chose the Utopia because I had an opportunity to "test" it on another owner's bike and it helped with the back strain I was experiencing. I also like the "clean" looks. The Utopia attaches through the seat and there are not any outside support bars that distract or interefere with the rider or passenger.
However, your question raises an issue I think Honda should be paying more attention to. Even with the help of the backrest, I am not saisfied with the stock seat. What is truly amazing is that every single rider in the local "commumity" I ride with shares the same opinion. Opinions vary and you will get a very "spirited" response if you bring up the question of who makes the best custom seat, but shouldn't we be getting a littler better saddle for spending over 20k for what is supposed to be the best touring bike in the world? Why do we as riders have to be looking to the aftermarket to get a decent saddle? I have considered the fact we are all different shapes and weights, but so are the peple I know who do not like the Goldwing seat. The very first weekend I had my bike I went to the dealership to check on some aftermarket parts I ordered. Three other GL riders pulled in at the same time and out of curisoity, interest to spark up conversation, whatever - I simply asked them how they liked their bikes. I was shocked over the intensity of the response I got - "great bike but the ******* seat sucks."
I would like to see a poll of how many GL owners replace their stock seats or add an aftermarket backrest. I can understand it if someone likes a particular look and wants gator, leather, snake, ostrich, etc - but we should not have to do it out of necessity to get a comfortable ride.
The Goldwing at a minimum should come stock with a backrest.
I have the Markland, It attaches to the grab handles on the seat
(NO seat cutting required) Easy to adjust, even while riding
Fits all 1800's so you can move it if you get a new one.
I love mine it does the job.
I believe any backrest would be about the same as far as providing support. I got the Utopia because it looks stock, no bars going down the side of the seat (better for passenger but also I don't like the look with the side mounting) and the price is great.
I am assuming (we all know what that does) that you are referring to the Utopia.
Because the only holes in the seat pan are sandwiched between the brackets, and therefore water tight, that this is a myth. The electronics under the seat are much more likely to get wet from road spray.
Another vote for the Markland... no cutting required on the seat... thus no ripping on the seat later... and unlike other backrests... the Markland
is adjustable forward and backward...
and if you decide on the Markland... a word of advise I can offer..
put anti seize on the chrome bolts BEFORE INSTALLING THEM...
The Markland not only adjusts forward and back, folds forward for passenger, has the storage bag and is very easy to remove. My 64 year old back needs the support and the ability to move forard or back to change seating position on longer rides. And, it matches the OEM seat.