All batteries need treating with respect.
The chemistry you choose, is more to do with how comfortable you feel with that particular technology. - You need to learn a little about your choice, and treat it with respect, use the correct charger, and don't abuse them.
NiMH is tried and tested.. But you need to be aware of the type you are using..
Standard cells will discharge over time, so you really need to check / top-up, every 3-4 months. - For EVERY pack!
LSD (Low Self Discharge) will hold their charge for many months, so if you charge after a running session, or end of season, they will be fine four months later.
Lithium-based, will attract 'the sky is falling in' tales, of death, destruction, and the end of civilisation as we know it.
Treat them with care. Understand a suitable charger, and my preference is to use a balance-charger. - Some packs, have smarter BMS (Battery Management System) boards, rather than just 'protection' which will do it all for you.
You pays your money, and takes your choice.
Personally, I use both.
PhilP