Li-ion is a phenomenal power source, but from my research, it doesn't really give a huge advantage until you hit the 18650 lights. With good quality protected cells and some common sense, Li-ion is pretty much as safe as any wall outlet, car battery, knife, or gas grill.
It is only significantly cheaper to run than Li primary disposables if you run your light fairly frequently, or buy batteries at a department/grocery store. They are very lightweight and have good cold weather performance and low self discharge.
All the advantages cost money and time though. If you don't see a specific need that justifies Li-ion, you're probably gonna be happy without them. NiMH rechargeables are so good now anyway.
As another "recommendation" I would suggest the NiteCore D10 if 14500 Li-ion were to become important. It gains no brightness over NiMH, but an extra 50% runtime and sheds 10 grams of weight.
The D10 is very robust, good clip, unique UI, awesome form factor and ergos, and seriously potent. If I was buying right now, it would be a dead heat between the LD10 R4 and the D10 SP.
If you are loyal to the L1T, then go with the LD10. Nothing wrong with rewarding a company that has been good to you, and by all accounts, the LD10 goes toe to toe with everything else in it's price/use category.