Like you, I researched and read a lot about isolators and dual battery kits. I settled on a 275-amp dual battery kit from Ironman4x4.com
http://www.ironman4x4.com/html/motorised275amp.html. I am VERY pleased with the kit. I installed the switch in a full-size Chevrolet Silverado pickup and plan to put the same setup in an FJ40 Land Cruiser.
The hookup is relatively simple, but I have to say that it was a bit of a pain wiring up the remote override switch. The kit is a good value if you don't have all of your wiring and connectors. It works flawlessly, and I purposely let the main battery die down just to check out the functioning of the unit.
The IronMan4x4 kit is made by BEP Marine, and the switch is a BEP Marine 701-MD
http://www.bepmarine.com/home-mainm...ote-operated-motorised-battery-switch-275amps. I found it online from $145 to $189.
I examined the National Luna and Hellroaring units as well. Both of these companies seem to make good products, but what really sold me was that the IronMan4x4 / BEP Marine dual battery switch is indeed a "marine" switch made for harsh and wet conditions which is perfect for under the hood of an off-road vehicle.
If anyone can source the "dual LED battery monitor," which is also made by BEP Marine, please let me know.