Hi Bob
Not used one myself, so can't comment on the actual lens, what I would say though is I'm not a fan of the 'all in one' lenses. The very large focal range is very tempting, but you'll suffer with the IQ and may not be happy with your results. Personally I wouldn't buy such a lens...
What other lenses do you have and what are you thoughts / reasoning for looking at such a lens ?
Hope this is of some help...