Judy, Welcome to the Hog Farm. :-D
Don't forget you have options.
I am a Tamron 150-600mm guy.
But there is another gun in town, The Sigma 150-600mm Sport model. It is also twice the price of the Big T, weighs 2 pounds more, and is weather sealed.
So before you buy, you might like to consider the SigZilla along with the Big Tammy.
My experiance has been interesting with my lens.
I started with DSLR photography last July (2014) and still call myself a rank amateur. But every time I venture out I am more pleased than the time before.
My "thing" is Humming Birds, and Grand Kids and soccer games they've been in since the were 3.
The Tamron has, in my experiance, a very tight DOF (depth of Field) and it has taken me literally 10's of
thousands of shots to figure it out. But that's how I learn, hands on.
Rather than continue to expound, or bable as one displeased jerk PM'd me, here is a link to a very recent thread about the Tamron.
http://www.uglyhedgehog.com/t-278646-1.html#4702802Maybe some of the Sigzilla guys can bring in some shots for you as well. Two I do know are
MT Shooter, and
Nikon DonBOK... Welcome to the Hog!
I look forward to any photographs you'd care to share. ;)
PS: If your disi, you might want to sit down or hold on to something.