Best I've tried was a Dingwall Super J with P/J pickups. It played beautifully, and I got used to the fanned frets in about 20 seconds.
Best I've owned was a 2006 G&L L-1500 with the #8 neck (1.5" nut, 12" radius). I ended up selling it, and about a year later saw a guy hang it up on the wall at GC after testing it, who said, "That's the best playing bass I've ever tried." (I know it was mine because it had the hex key saddle adjustment screws I installed.) It really was spectacular in that respect. I now have two G&L's with the #8 neck and they both have excellent playability that's close to that L-1500, but not quite there.