This is from another thread of someone asking pretty much the ame thing. They started with a slim ecig and now want something better. Sorry Im lazy and since Id be writing basically the same thing, Im just gona copy and paste it.
I def recommend going with a bigger battery PV. As youve noticed already, slim ecigs need to be charged a LOT.
The eGo is a popular model and alot of people use them. Personally though, I agree with wv2win and prefer the 3.7V PVs over a 3.3-3.4V eGo. I would check out the kGo, E-Power, and newer Riva(3.7V). All 3 have 510 connections and give a great vape. Any of them would be a LOT better than what you have now and are actually the same price if not cheaper than what you paid for your current kit. I have an E-Power and love it. The main difference between the E-Power and Riva/eGo/kGo is that the E-Power uses non-proprietary batteries. Also everything on the E-Power is replaceable so it really helps keep maintanance costs down. E-Power batteries cost $4-5 while eGo/Riva/kGo batteries cost $14-20. E-Power batteries are 1050mah and I get avg a day to a day and a half on one battery. Because of the non-proprietary batteries I find it alot easier to carry a spare battery. With the Riva/kGo/eGo you basically have to carry a second PV to have a spare battery. With the E-Power you can just throw a spare battery in your pocket and if needed unscrew the switch and pop in a fresh battery. The E-Power batts are about the size of a AA but alittle longer so its easy to carry one in your pocket or bag. I also like that everything is seperate and can be replaced individually. With the Riva/kGo/eGo, the tube, battery, and switch are all one piece. So if your switch fails or you need to replace a battery, you have to replace the whole unit. With the E-Power, the tube, battery, and switch are all seperate, so if you need a new switch you can buy just a switch and keep using your existing tube and battery. Crystal Clear Vaping has a great deal on the E-Power and you get $25 in free stuff, plus free shipping.
If I hadnt gotten the E-Power, I def would have bought the kGo. Besides the proprietary batteries which Im not a huge fan of for the reasons stated above, its a really solid PV. The batteries are 1100mah so they last a long time before needing a recharge. The kGo gives a great vape and most people that use a kGo love it. Hoosier Ecig Supply has a good deal for the kGo.
The Riva is also a nice PV. If you get a Riva, make sure its one of the newer ones that are 3.7V. The older Rivas were 3.4V like the eGo. The Riva has different size battery options you can choose from and is very affordable. LiberyFlights has a great deal for the Riva, just remember to hit the 20% off button first.
The eGo is also a popular PV and works well. It is 3.3-3.4V though, and while I personally think the 3.7V PVs give a better vape, the eGo is still a nice PV. Many vendors carry the eGo and even more carry eGo knockoffs and clones.
With the eGo and Riva you have the option to get a passthrough battery.
Another plus to the bigger battery PVs is that you will be able to use low resistance attys and cartos. Slim ecigs can only use standard resistances. Low Resistance (LR) is considered 2.0ohm and below. LRs give a warmer vape and more TH and most people prefer them. Another reason I like the 3.7V PVs more than the eGo is bc they handle the lower resistances better. The eGo can handle LRs, but personally I dont recommend using below 2.0ohm on an eGo. Using a 1.5ohm or 1.7ohm on an eGo can potentially fry the battery, the 1.5ohms are the most likely to fry the eGo. Many eGo users use below 2.0ohm and havent had a problem, but theres also alot of people that have fried an eGo using them. Really youll hear both sides. Many eGo users will say that they use below 2.0ohm without a problem, and then many others wil say dont use below 2.0ohm bc theyve either fried one or know someone who has. 2 of my good friends both use eGos and bought them from the same vendor. The one uses 1.5ohm DCs, which stresses the eGo the most, and has never had the slightest problem. The other one fried his eGo last weekend using a 1.7ohm Ressurector carto. Even though the 1.7ohm cartos dont put as much stress on the eGo mosfet as the 1.5ohms, his eGo still fried while my other friends hasnt. So its kind of a crapshoot and if you do get an eGo its hard to tell what it can handle and what would push it over the edge. Thats why I dont recommend using below 2.0ohm, just to be safe. Thats also why I like the 3.7V PVs more bc I like the lower resistances and the 3.7V PVs handlethem better. I use the 1.7ohm Ressurector cartos on my E-Power. They are designed for 3.7V PVs and work great on the E-Power, kGo, and Riva.
Really any of them, including the eGo, I think youd be really happy with. THeir all good PVs and will be a big upgrade from what your using now.
Goodluck with everything!