Use soft words and hard arguments.
Proverb

Examples of websites developed by Burst!Open / Internet Lynx and driven by open-source applications:

MPI Ultrasonics Bookstore (Zen cart)

Ultrasonics World Store (Zen cart)

International Magnetic Solutions Store (Zen cart)

ClonePanel (WordPress with integrated Vanilla forum)

Burst!Open (WordPress)

Solar Dream House (WordPress)

Cheers Maps (Joomla)

Powerultrasonics (Xaraya) – coming soon!

Powerultrasonics Forum (SMF)