I have a Vamo V3 and V5. Although I am quite pleased with it and still use it daily, it is just one in my rotation. It's been extremely reliable, and will work well if you take care of it. Using Ohms Law Calculator, running the highest volt and the lowest ohm coil gives a maximum output of 5 amps. Although that means you have a wide variety of batteries, it doesn't mean that all are safe. My personal choice would be to go for a hybrid battery. IMR batteries, although safer for mechanical mods, usually have lower milliamp hours than hybrid or ICR. here's a brief explanation of the different types.
ICR- high Milliamp hours (longer run time) but cannot be pushed too hard.
Hybrid- Safer than ICR, have slightly less Milliamp hours than ICR batteries, but can be pushed a bit harder than ICR.
IMR - Safe Chemistry battery. Lower miliamp hours than the previous two but can be pushed much harder than both hybrid or ICR.
The Vamo doesn't need IMR batteries, and with a 5 amp limit, it will reach only half the limit of most hybrid batteries.
My first choice would be the Panasonic batteries. the 18650PD/18650Pf are rated at 2900MaH and should last a long time. I use the PD's in my Vamo, and they work extremely well. The PF's are a newer version, but both work fine. They can also be gotten at a good price
HERE if you're willing to wait a while.
I have used Trustfire 3000MaH in my Vamo with no problems, but I'd rather go for the safer Panasonics. Besides, the 3000MaH is actually 2400MaH, and the Vamo can run them at their max output. Besides, anything with the name "fire" in them should not be trusted to be totally safe.