Their are def some nice devices out now that have long battery life. I use an E-Power and get about a day to a day and a half on one battery. The kGo also has really good battery life and can last thru and a whole day. They are both like eGos, but are 3.7V instead of 3.4, and the E-Power uses non-proprietary batteries so its alittle different in that way compared to an eGo.
The Riva is also a great PV like an eGo that is hassle free and affordable and 3.7V.
Personally I think that you need to mess with clearomizers more than a lot of other cartos. If you get a 3.7 device like the Riva,E-Power, or kGo, the Resurectors are really popular cartos that are easy to use. They also hold 2ml of juice so they dont need to be refilled often. The Boges are also popular hassle free cartos that work well on a 3.7V or an eGo. Many normal cartos work great and are a lot less finicky than the clearomizers
Theres quite a few great PVs now that are easy to use and work really well! I think you can def get something youll be very happy with!
Goodluck with everything and if you have questions just ask.