Tamron SP AF 17-50mm F/2.8 compatibility with nikon d5100/5200?

I want to buy a a dslr camera. I have searched in the net and found nikon d5100/5200 can be a good one to buy. Now I find some images of Tamron 17-50 mm f-2.8, which are really very nice to see. Now if it may have a auto focusing problem in d5100/5200 becz they don't have in built motor. But still if I want to buy the tamron 17-50 for d5100 or d5200 then how it will be comfortable? If someone has used that particular lense with d5100, can please tell me that how much one has to face difficulty in focusing something and how is the overall experience of d5100 and tamron 17-50 mm? Is it worth to buy?

If you had gone to the Tamron website, you would have seen that the lens does have an internal auto focus drive

You would also find that this lens has a 6 year warranty, not bad at all.

http://www.tamron.co.jp/en/lineup/b005/

On their website it is written in the compatibity that nikon (buit in AF motor).So how it will behave with nikon d5100 or d5200?

Read the description carefully. I have a non OS (optical stabilized) version without the built-in autofocus motor. It works fine on my D300 and D90, but wouldn't be compatible with your D5100/D5200.

It's a relatively light, and sharp lens. For a while, it was my go-to lens for closeup, low-light situations until I bit the bullet and got a Nikon 17-55mm AF-S f/2.8. The one problem I've read about and actually had with that lens is that the front ring can and does work loose. I've had to do some tightening a couple of times.

As far as comfort, it was a small lens for my D300, but it's a perfect fit for the smaller bodies, such as your D5100/D5200.

Autofocus was quick and sharp. Images were crisp and had excellent bokeh. Here's a review.
http://www.bythom.com/1750lens.htm

Here's some images shot with a d5100 and that lens.