There are a number of reports of poor battery life with the Plextor E12 controller and then some reports of ok battery life. This is the first I've read of with an older M9Pe drive and a Marvell 88SS1093, but it doesn't surprise me.
It seems to depend on a number of factors, including drive usage and how much RAM you have (which drives how often it is spooled to/from the SSD). The condition of your battery also matters a lot. Writes typically use more watts than reads, etc. Transferring writes from the SLC cache to the TLC/QLC storage can also eat power in the background.
Power efficiency per GB transferred is, IMO, a poor predictor of battery life. Some controllers are worse at power management than others, and some like the E12s use more watts at full blast. Older designs, like the Marvell you have, use more watts at intermediate states and at idle.
And some NAND (ie Toshiba BiCS) seem to generate more heat than others (NAND runs faster when hot).
More watts = more heat = more work for the fan to cool the laptop, and that means less battery life. To some extent a fast controller with better power efficiency helps with this, but not if it uses more watts at full blast for frequent short writes.
I have a 13" 2013 rMBP with 16GB RAM and added the Crucial P1 1TB (QLC). I get +/- 6 hours on a charge, more if I keep Google Chrome closed (a power hog). I replaced my failing battery at the same time I did the drive, so I can't give accurate before and after comparisons.
I also own the Sabrent Rocket 1TB (E12 controller), and use it in a desktop. I measured the temps and saw it runs hot under heavy loads (e.g. benchmarking, large file writes).
In general, my experience has been that the SMI controllers with Intel/Crucial NAND seem to have better power and thermal management than the Plextor controllers. But battery life is very SSD model and use case specific.
Less subjectively, Anandtech always includes power management information in their reviews, and the guy at guru3d.com uses a thermal imaging camera in his SSD reviews.