"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
AirPods and AirPower: Everything We Know
Solid State Drives (SSD) Reduce Battery Life?
Tom's Hardware seems confident in their results and compared four different Flash SSD drives to a traditional hard drive. The results either showed no change in battery life or up to one hour (14%) less battery life for the test system (Dell Latitude D630). Testing was performed using the MobileMark 2007 benchmark which specifically measures battery life performance under "real world" usage. Despite the worse battery times, the SSD drives did outperform the traditional hard drive by a significant margin.
The only Mac which currently ships with a Solid State Drive option is the MacBook Air. Battery benchmarks for the MacBook Air showed modest gains vs no gains depending on the reviewer. It has been widely expected that Solid State Drives will become more available as prices on Flash memory drops. Besides improvements in performance, SSDs are also believed to be less prone to data loss.