The mk I version of this lens is very good so it was surprising to me that Canon should choose this lens for an upgrade. As it turns out the new IS II series of lenses are truly remarkable, the improvement over the previous version of Image Stabilization is almost magical. Combined with the wide maximum aperture of F/2.8 and the closer minimum focus distance this is a very versatile lens.
The lens is slightly heavier than its predecessor and some folks have said that the out of focus bokeh is not as nice as the previous version or that the out of focus blur is not as smooth. I can see what they mean but really it is just slightly different and still good. Another feature of this lens that reflects its quality is that it remains sharp wide open and throughout the zoom range.
This is a top travel lens, and there are a few things you can do with it that make it well worth taking with you. The mk II has a closer focus distance than the mk I which is great and also means that you can almost use this as a macro lens as is, however if you add an extension tube and/or a D500 screw on close up lens you have a pretty good macro at little additional cost or weight. When using it as a macro lens you will want to generally stop down the lens to increase the depth of field and here it still performs quite well.
Another option is to use the lens with a 1.4x mk III or 2x mk III extender. Of course extenders result in slight loss of contrast and sacrifice 1 and 2 F stops respectively. However I have seen some tests that show that even with a 2x extender the lens is quite close to the same quality of a 100-400 L IS which is itself a pretty nice lens. However, generally I recommend limiting use of extenders to 1.4x and even then only on high quality lenses.
To summarize this lens review, the 70-200 mm F/2.8 L IS II is great lens and excellent for travel photography. The alternative is the lighter F/4.0 version of the lens, but for my way of thinking the faster lens is worth it.