Hi There,
I can provide some details about my experience with vTiger but can do that on personal messaging.
You can however take a look at my profile and past jobs.
We are one of the oldest vTiger experts working on Freelancer.com
Also we are the authors of famous Module Builder and Echosign, Docusign, Google Drive etc.
Kindly send me a message and I would walk you through my credentials.
Your work is in safe hands.
Regards,
Amit Kajale (Jerry)