RE: What are the benefits of going Lipo vs Nimhs?
If you do used a brushed ESC with a LiPo, just be sure it has the proper LVC (low voltage cutoff) for the LiPo. Many of the older brushed ESCs have only NiMH/NiCd LVC levels.
I started using 2S LiPo packs in my brushed surface vehicles, and those ESCs don't have the proper cutoff voltage, so I purchased some 2S LiPo low voltage alarms to let me know when they are getting close to the min voltage. With an aircraft, this type of alarm may not do the job, though (too far to see or hear).