No-one can decide for you, however, some factors to consider.
- Convenience. You can walk around all day with a single lens, no camera bag.
Which you have to weigh against...
These super zooms are slow & are not very good in low light. That f3.5 is really only there at short focal lengths; they quickly close down as you zoom.
They tend to be very soft at anything over half their zoom range, & some of them are reported to have noticeable colour aberration at the long end too.
They vignette at short lengths, though the camera [& photoshop etc] ought to be able to compensate to a reasonable degree.
They're APS-C only, so won't move with you up to full frame.
Taking all this into consideration, personally I went with the Nikon 18-300 instead; it purportedly has better image stabilisation & less colour aberration. It still has all the other down-sides mentioned above, but it was cheaper & honestly, it's not bad overall.
In good light the Nikon's AF is actually really snappy, far better then my Tamron 70-300 in similar conditions, though the Tamron is actually a good deal sharper at 150-300mm.
The convenience outweighs the other factors especially if you're on a family trip rather than a photographic expedition.
The limiting factor on a family trip is the other members' patience.