This is the first time I've had to sharpen my RAT3 since I got it 3 months ago. First I roughed it up a little on my Cabela's diamond stone then I went to the Lansky Ceramic rods. I have the one with the pre-drilled holes that set the rods at pre-determined angles; crock box I think it's called. Anyways I first tried the coarse rods on the more open angle and the fine rods on the smaller angle and this usually works well for my other knives, however this D2 proved difficult. I stropped endlessly on my Jemco strop on the leather and on the underside strap. Still nothing. I finally tried coarse rods on the small angle holes and then stropping to no avail. What's the trick to D2?
Do you know how much of a jump in grit you're making from the diamond stone to the ceramic? If the diamond stone is pretty coarse, the ceramic might to too fine to effectively refine the edge from the diamond stone. Stropping would have the same problem doing much to a coarse edge from the diamond stone. With D2, the problem would be even worse since it's a very hard steel.
As for what method is better, that's pretty useless to you since you don't have a complete set of diamond stones in different grits or a set of paper sharpening wheels.
If you're in the market for something new, I personally recommend the paper wheel setup. That will work for any blade steel you come across and if I can learn to use it, anyone can.

I say this purely based on the ease of use, time saved, and cost. For about $150 bucks, it will easily give you a hair popping edge on any knife in less than couple minutes each.
If you stick with diamond stones, it sounds like you'll need a few more to gap the grit steps and perhaps a few more strops.
Regardless of what you choose, there's no steel made today that can't be sharpened by either system. It comes down to experience and practice.