As a general guide:

Low End - E bay, Boot sales etc. -   Probably uses a digital prosumer or entry level DSLR.

Mid Range -  small to medium size business, etc. -  Probably uses mid to high range DSLR.

Top End - Glossy society magazines etc. - Probably use a medium format with digital back.

 

Which is best for you also depends on your level of skill in using the camera and lights. If an inexperienced user you will get better results with a prosumer cam.

If your main interest is taking the photographs and you have some experience you will get better results with a DSLR

If you are solely interested in the photography and have a high skill level the best results will be obtained using a medium format.

And every one said, 'If we only live,
We too will go to sea in a Sieve,---
To the hills of the Chankly Bore!'
Far and few, far and few, Are the lands where the Jumblies live;
Their heads are green, and their hands are blue, And they went to sea in a Sieve.

Edward Lear
http://www.nonsenselit.org/Lear/ns/jumblies.html