So I played a quick game against a friend last weekend (we agreed it was experimental and would not count towards our scoreboard).
I was the axis and picked two national advantages: naval night-fighting and nazi scientists.
The allied player insisted on also having two national advantages, so he picked colonial garrison and flying fortresses (I forget the name, it’s the non-LHTR national advantage; US bombers are immune to AA).
Colonial Garrison gave me a lot of problems! He placed the IC in India, which I went for right away, but the allies managed to trade it for a few turns, and then the US player waited till I was in a bad situation and bought two factories in china and sinkian.
The battleship advantage was not that great. It was fun for a couple of battles, but then the US player just avoided my battleships. I was a few turns from opening the suez canal, and my fleet was prepared against africa, but the US player was going to provide quite a hassle.
The game ended prematurely; I suspect I would eventually have lost. The nazi scientists got me a tech upgrade only after 10 tech buys.