Jumping in as a former Hybrid owner, I have jumped other vehicles both from the posts in the engine compartment and the battery in the trunk. No difference.
Never had to hook up a charger to my battery but I do not see a valid reason to use one location over the other other then convenience, both should accomplish the same task. I think it is easier to use the hood posts and easier to see rather then go through the trunk access door.
I believe I once hooked up a charger/booster battery to the hood posts while changing the actual battery. I did this to maintain all the memory settings,... worked fine, just have to be careful because the cabling is live..