I have the 55-200 and just recently got the 50-140. I almost always shoot on the wide side, hardly ever shoot long. But when I did, I found the 55-200 somewhat lacking because of the focus speed and chromatic aberration. Although the 50-140 is a much larger lens, having come from behemoth Nikon f2.8 lenses made the fuji seem very manageable. The focus speed is much faster. The OIS is far superior to the 55-200. I've been able to shoot at 140mm and 1/8th second and get good images in low light. It's a joy to just play with because it's so good.
I thought to keep the 55-200 for when I travel, but the more I use the 50-140, the less likely that is. If you can afford it (it ain't cheap) grab it!
I am basically down to the 18-135mm for real-world shooting when I'm traveling, as it's a good compromise regarding focal lengths, 5-stop OIS and size/weight. The 50-140 is better from an IQ and performance perspective, but it's also much larger and heavier, hence much less of a general-purpose tele zoom for me.