As far as the usefulness of the 90 degree adapter goes....I did have an issue with my original straight Marinco plug...it lost the neutral wire within the connector causing all sorts of issues within the RV, no damage though. It was at this time I decided the weight and strain on that contact was relatively high so when replacing the cord end, I also got the 90 degree accessory. No further problems in roughly 10 year's of use but maybe I wouldn't have had problem's anyways...:)