Most design firms will go with V-Ray simply because it's cheaper and the licensing structure is less restrictive (no limitation on render node installs), as well as distributive frame rendering which is very useful for producing high-res stills.
Brian nailed it -- both will do what you want, it comes down to preference.
You're right about it being a standard question as a quick search reveals:
http://www.cgarchitect.com/vb/13951-vray-brazil.html
http://www.cgarchitect.com/vb/13959-gonna-mad-renderers.html
http://www.cgarchitect.com/vb/6157-3rd-party-renderers.html
http://www.cgarchitect.com/vb/5031-brazil-v-ray-mental-ray-what.html
http://www.cgarchitect.com/vb/3692-rendering-plug-ins.html
Shaun