V2 Vsavi EX Battery

I've been using these for a couple of years now, and I'm on my 7th battery. I have three on the go permanently - two that I'm taking to work, and one which stays at home - which means that I always have a battery fully charged up and ready when I need it. They tend to lose capacity over time, but with three in rotation, they last much longer (a year on average - one even lasted two years before I finally let it go).
One downside of the automatics is that sometimes the "suck" detection isn't working well - you have to draw quite hard before the battery turns on - but customer services are quite helpful when there's a problem.

Excellent

I already have a couple of the manual versions but as they are a few months old they no longer hold a charge for as long as they used to so I ordered another, when it came i could not get any 'draw' from it despite changing the rubber ring, cleaning the air holes and resetting it.

I informed customer services and Vicky has sent me a new one straight away which works perfectly and I didn't have all the hassle of sending the non-working one back, so well done customer service.

Lasts well and clear when it needs recharging

I think the style and colours of the V2Ex batteries are great. I am however conscious that they do not seem to last all that long a time. They start to run down quicker and the charging time lessens and I have had two batteries that after being charged, released from the charging device and left on the kitchen granite counter, they suddenly become too hot to touch and the 5 tiny holes which light up and indicate the battery power starting blinking light crazy. Rather alarming and I quickly placed them on the concrete outside the property.