Are their advantages to a NimH battery vs a Lithium Battery?

Our first Prius was a 2005 Gen 2 with NiMH. We kept it 10 years and put on 145K miles. Toward the end, the battery would not maintain state of charge (SOC) at all. The slightest demand on the battery, primarily going uphill, would cause it to fall to the bottom two bars, which turned purple if I recall. MPG was in the mid-40's.

The opposite occurred coasting downhill. The battery would fill all the way up and required use of B mode to save friction braking, because regen braking was disabled when SOC was full. We never reconditioned the battery, and eventually sold it for a Gen 3. We had two more Gen 3's but never kept them long enough to experience decreased battery performance.

Eventually, we got the 2016 Gen 4 with the Lithium battery when it came on the market. We now have had it 9 years and have 90K miles. There is no degradation of battery performance and still get high-50's MPG consistently. It's only one data point, but I believe this demonstrates the Li-Ion battery is superior to the NiMH.

 

i think lithium is the way to go.
toyota says not for very cold places, but we have plenty of midwest and canadian members with good lithium reports.
other than that, i can't think of any downsides.
the gen 3 plug in prius from 2012 has shown excellent high and low mile characteristics, and great longevity to date.
i can only think gen 4 is even better.