The reason toyota got in in OZ was there was not a modern landrover product to compete against them upto the discovery launch .
The idea of their reliability ? I towed enough of them in ,as part of my business in OZ , to realise they were as reliable as most other 4x4 when subjected to what 4x4 were supposedly designed for They often used to ask why have you got one of these (refering to my 130DC HCPU ) ? my reply : You cannot tow a L/Crsr or nissan patrol on a trailer with another l/crscrsr or patrol legally you can with a Defender 7450KG train weight in OZ
The defender is not involved in JD Power survey AFAIK