I switched from Blu to the Volt from Smokeless Image and I love it. I have two 78mm
batteries and each one will last me about half a day at the rate I vape. For the short time I had the Blu, there was one or two instances where I'd run one battery down while the second was still recharging. Smokeless Image also offers larger batteries now which can last around 13 hours or so. Another advantage of going with the Volt is that it's compatible with some gear from other sites, as it's a standard size.
You can get either prefilled cartridges or blank ones so that you can fill your own with whatever
juice you like if their default flavors aren't your style. I can get too much of a throat hit from certain juices, so I'd say the Volt might be what you're looking for.
Here's their website so you can check out some of their kits. It's always recommended to get more than one battery.
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Also check out their X2 battery selections for longer battery life. And if you post a picture of yourself using a Volt in their subforum here, they'll ship you your choice of either a battery, a bottle of juice, or a pack of cartomizers for free.
Another option, if you're ready to leave behind the cigarette style PV's, is to upgrade to larger systems. I don't know a darned thing about these myself, but a veteran should be able to help you out.