I have a lot of experience with AA rechargeable. eneloop and many others AA are 1.2 volts. Most all on the market rechargeable are 1.2 volts some better than others. The real issues is what is the radios real operating requirements. Then it comes down to what is your batteries amps. Low amps equal less working time in any radio. Transmit often and it get a lot less.
In photo you see two version of the eneloop’s and the new Li-po rechargeable. The eneloops have poor lasting power. moreover, they are not enough voltage. The new LI-po AA and AAA rechargeable all have high mWh ratings.
I have a set of MidlandGTX1000 and a KG935G with a extra battery pack using the Li-po’s I am very happy and is worth the extra cost. The Li-po are not in the major markets yet. They are designed for a special charger. so fully charged then in the stock radio charger port is not recommended. But I have tried it and it works. The deleePow are amazing. they power drain is concsten till the very end, then bang there dead and need recharging.