Frank from iSO Network upgraded my Zen Cart recently. It was a major upgrade from v1.3.8 and I couldn't handle it myself. He went out of his way to make sure the transition was smooth and the site running perfectly. It was a tricky upgrade and he worked above and beyond what I could have hoped for to get the job done, and quickly. I highly recommend iSO and I'm definitely a customer for life.
Deb T, Colorado, USA