I would consider getting a 3.7V PV over an eGo. The PV your using now is 3.7V. Going to an eGo would actually be a downgrade voltage wise since the eGo is only 3.3-3.4V. Check out the kGo, Riva, or Epower. They are all 3.7V PVs and have 510 connections. They are all similar in size and price to the eGo. Personally I find that a 3.7V PV gives a better vape than an eGo and they handle the lower resistances alot better. Using 1.5ohm or 1.7ohm cartos on an eGo puts alot of stress on the eGo MOSFET and can fry it if your not careful. Personally I wouldn't use anything below 2.0ohm on an eGo, but that's up to you. Many eGo users use below 2.0ohm and have never had a prOblem, but there's also alot of people that have fried an eGo using below 2.0ohm. The 3.7V PVs handle 1.5 and 1.7ohm cartos alot better and are alot less likely to ruin your battery. I would get a kGo or Epower. Personally I use an Epower and love it. Everything is replaceable on it so it's cheaper to maintain and it uses non-proprietary batteries unlike the kGo/eGo/Rivas. Epower batts cost $4-5 compared to eGo/kGo/riva batts that are $14-20, and they last alot longer before they need to be replaced. The batteries are 1050mah and I get a day to a day and a half on one battery. I also find it alot easier to carry a spare battery with you. With a proprietary battery PV like the eGo, if you want to carry a spare battery, you basically have to carry a second PV. With the Epower you can just carry an extra battery and swap it out if needed. Epower batts are about the size of a AA but alittle longer so it's easy to throw one in your pocket or bag.
If I hadn't gotten an Epower, I def would have gotten a kGo. The kGo gives a great vape, and the batteries are 1100mah so they last a long time. I just liked the Epower more bc it's alot cheaper to maintain since a replacement kGo battery costs almost $20.
Either one is a great PV though, and would def be better than an eGo.
Crystal Clear Vaping has a great deal for the Epower and you get about $25 in free stuff. Free 5-pack of Ressurector cartos, free 30ml juice of your choice, and free shipping. Plus put in ecf5off and you get 5% off the order. It's an awesome deal and gives you everything you need to get going.
Hoosier Ecig Supply and DarkCity Vapor both have good deals for the kGo.
For either one I would def try the Ressurector cartos from CCV. They are absolutely awesome and give a great vape. They are 1.7ohm and hold alittle over 2ml of juice so they last a long time before needing a refill. They are designed for 3.7V vaping and work great on the kGo, Epower, and Riva. They will work on the eGo too, but don't run at full potential. Becareful using them on an eGo though, many eGo users use the Ressurectors with no problems, but my buddy fried his eGo using a Ressurector 2 weeks ago