I had the 18-135 for a couple of weeks and I sold it quite disappointed of its IQ, not bad but quite lame when compared to the general fujinon quality, at least my copy. Totally another kettle of fish when pitted to the 'fijicrons' in the IQ department. Bulky and heavy BUT phenomenally good OIS and convenient range, so for video it's quite an asset. But I rather go with the usually snubbed XC16-50 zoom. It's sooo light that it's a bliss, INVALUABLY feather light when traveling, better IQ, very good wide angle range at 16mm and quite decent for video but much worst OIS than the 18-135's one (its only shortcoming). All in all a win win lens on a dirty cheap price! On the other hand the 55-200 IQ is as good as it gets, also very good OIS (almost to the level of the 18-135),quick autofocus and surprisingly good for video, a must for sports. I use it every weekend for sailing and it's a boon at an affordable price second hand (got mine for little short of 400€. So in a nutshell, grab the 50-200 and look for some light fujicrons like the 18, 35 f2 ... To my taste better to carry two small bodies like the xt10-20 and xe3 than the 18-135. By the way, very little difference in photo image quality, if at all, between the xt10 and the new XE3 but substantially better video capabilities and much better autofocus.
Any way, the 18-135 is quite a decent lens, better than most of our skills, but Fuji has better options for price/weight/IQ balance.