Are newer fluorescent fixtures significantly more efficient then older ones?

I pulled down five fluorescent fixtures in the garage when I dry-walled it and painted it white. Now its brighter and requires far less lighting. I need to decide which two of the previous mismatched fixtures to reinstall. Two of them are clearly older and sturdier. "They just don't make them like they used to" definitely applies to the newer ones. They're so flimsy that I could probably dislodge or break the bulbs by manually twisting the frame. The ceilings so short in the garage so they will probably get struck at some point, possibly by my head. On the other hand energy efficiency has only increased over time, I don't know if that's all because of new bulbs or if the fixture is also to thank. So I have three options: Use the older fixtures as they are Pull the guts out of the newer fixture and put it in the sturdy older fixture Use the newer fixtures as they are (assuming above is too complicated) Any related feedback is appreciated.