Personally, I'd say the top two companies are RDL and Diamond/Hartco but a seat is too personal to say one company is the best. I have the RDL and like it better than the others I've tried. There are very few complaints made about RDL and I've seen several complaints about Ultimate. But you don't know until you try them out.
Have a Russell and love it. Stock seat broke down after about 50K miles, so got a Diamond. Was OK for me, but not for Carol. Got the Russell, and like it well enough to get another stock seat to put back on the wing when it leaves, cause the Russell is going on the next wing.
Had a 1500 the stock seat broke down in, got a Travelcade. Most uncomfortable seat I ever sat on. Made 100 miles feel like a marathon. Just got a new stocker, and it worked just fine.
THIS IS JUST MY TWO CENTS WORTH,,BUT IF I WERE YOU I WOULD CALL MARK WITH HARTCO/DIAMOND SEATS IN FLA....IVE HAD TWO,,,THE SECOND BEING ON MY 05 CBC1800,,AND I PROMISE,,,YOU'LL NEVER RIDE ON ANYTHING ELSE...HAD THE FIRST ON MY 99 1500.
GOOD LUCK AND SAFE RIDING,,,