are there knowledgable sales people available at all times during business hours?

I agree with the other answers. It's a great place with a knowledgeable staff.

There are friwndly and knowledgable people everytime i went.

Yes

In my experience every time i have been in there are knowledgeable people... and friendly.

There are, for every camera brand or gear ,you will have a person who specializes in it

Definitely!

Yes. The whole staff is very knowledgeable. They have answered every question I have asked, and they are very professional.

I have purchased everything from a camera harness to camping tripods to a Nikon D4 here and they have always given me great advice without breaking my budget or acting like those high pressure sales people. Certainly the best place I know of anywhere near Arlington. They have even referred me to specialty shops when service I ask for isn't something they handle.