I have read the PDS for both Marsh (Insure my Tesla) and Redbook, they both cover the same components under the same conditions except, Redbook pay more for hotel accommodation, towing, car hire and have unlimited kilometre coverage.
When the extended warranty was announced by Tesla, I was led to understand that Marsh was going to be offering a introductory cheap extended warranty coverage. If this is it, I would hate to see what it is in the future.
Considering this and the premium is significantly less than Marsh. I'll be going with Redbook for my 2015 P90D . Details are below if anyone is interested
Marsh - Extra 4 years (total 8 years) up to 160,000km: Total Premium: $6,295
Redbook - Extra 3 years (total 7 years) UNLIMITED klms: Total Premium $2430