Here's my 2 cents worth. Although I haven't seen the ultimate bunks themselves, I believe they are of a similar material as to what Popeye has on his rig. And, what Popeye has on his rig is of a similar, if not identical, material as white plastic cutting boards. See what I am getting at here?
On my last boat, I made my own bunk slicks out of cutting boards. Just painted the board black, and installed the slicks on top. They worked flawlessly, well except for the slippery part. For the way I launch and load, carpet is the only way to go. But, if you feel that the slicks (as Brine mentioned, they are very similar to rollers) are necessary, save yourself the cash, and get a few Walmart 3/8 cutting boards, rip them to width, and install them with countersunk stainless screws. Be sure to countersink them in real deep.
Now, seeing as slicks have similar affects as rollers, lets look at the advantages of roller trailers over bunk trailers. Roller trailers, for the most part, are designed for steeper ramps, in areas where power loading isn't legal/practical. As in, they are made for winching pretty much the whole way on, just as Russ does (however, seeing as his boat is a bit lighter than a 20 foot bowrider, he pulls his on most of the way, as opposed to winching it).
Where I fish, we have well maintained concrete ramps, and most of the time, I have my outboard. Thus, when fishing double, and launching, I will either unhook my winch at the top of the ramp, or when the trailer is about at the water depending on conditions, then whoever is fishing with me will back me in the rest of the way, and the momentum from backing up will continue my float past the trailer. Can't do that with slicks.
When I load, either by myself, or with someone, I back the trailer in to where when I idle onto the trailer, I stop about a foot or so from the post. Then, I give it a little gas, and the boat slides up to the stop, centering itself, and it stays. Then, I can move about the boat, to go up front and hook my winch strap up, without it sliding down, or if trying to get a lot of boats out after a tourney, my partner can start to pull out immediately after I get the boat on, even without the winch strap. With the slicks on my old boat, I would slide back down, so loading was always a two person job. One person to drive the boat on, and the other to hook up the winch strap.
Personally, I am going to keep sticking with carpet, or if I can find a material with the same characteristics, but better durability, that would be ideal.
