I have the Tamron 18-200 which typically is a lot cheaper than the 18-250 since it is an older model ($249 from B&H after rebate). I like it, particularly at the local Dog Park. I can catch distant dogs running and quickly catch the dog standing at my feet looking up at me!
Some people would never buy a super zoom because it does not have the image quality of the four prime lenses needed to do the same job. I don't have the budget for that many primes nor would I want to change between them at the dusty dog park.