Do NOT get either of the first 2 ecigs you mentioned. They are both very basic but are also very overpriced too. You can find a much better kit. For a slim ecig, the Volt from SI, ones from Vapor4life, Bloog, and Halo g6 are the only decent slim ecigs. If you really feel you must get a slim ecig, get one of those. They are the only ones that arnt overpriced and people seem to thing their okay. Even the best slim ecig is going to have a small battery and slim ecigs can only use standard resistance attys and cartos so your limited to what you can use.
A bigger battery PV will give you a LOT better battery life and alot more options since they can use standard resistance attys/cartos, but also low resistance attys/cartos too, which most people prefer.
The eGo is a popular ecig and it does work well, but I would also check out the E-Power, kGo, and Riva.
The E-Power, kGo, and Riva are 3.7V PVs while the eGo is only 3.3-3.4V. They all have 510 connections and are similar is size and all in the same range price-wise too.
Personally I would say go with a kGo or E-Power. They both have great battery life and give an awesome vape.
The kGo has 1100mah batteries and the E-Power has 1050mah batteries. The biggest difference between the two is that the E-Power has non-proprietary batteries, meaning that you can remove the battery and replace it, like you would do on a flashlight. I have an E-Power and love it. Being able to remove the battery was on of the thing I really liked about it bc I could just carry an extra small battery with me and unscrew the switch and pop it it if needed. With the eGo/kGo/Riva type PVs, the only way to carry a spare is to carry a second PV bc the battery is part of the unit. I also dont like with them that if you need to replace a battery or your switch fails, you have to buy a whole new unit bc its all one piece.
With the E-Power everything is seperate and every part can be replaced individually. If you need a new switch, you can buy just the switch for under $10, and keep using your existing batteries and tube. E-Power batteries are alot cheaper too and cost $4-5 compared to eGo/Riva/kGo batteries that cost $14-20, and the E-Power batts last a lot longer before they need to be replaced. You can buy 4 E-Power batteries for the cost of one eGo/kGo/Riva battery so its cheap to get a few andnever have to worry about being stuck with a dead battery. I get on avg a day to a day and a half on one battery, but always carry a spare in my pocket or car just in case. The batteries are about the size of a AA but alittle longer so its easy to always have a spare with you.
I would check out Hoosier Ecig Supply. They have the kGo and E-Power there fr a good price. Both kits cost $43 there.
Crystal Clear Vaping also has a good deal on the E-Power. Its $57, which is more, but you get about $25 in free stuff so its actually a better deal bc you get free Ressurector cartos, free 30ml juice of your choice and free shipping.
Put in "5off" on Hoosier for 5% off order, and put in "ecf5off" on CCV for 5% off.
Boththe kGo and the E-Power give a great vape and are actually cheaper than most of the slim ecigs. I got my E-Power from CCV, but I would prob get it from Hoosier right now bc they have the new switch already and CCV wont have it for another day or 2. I would buy a spare switch from Hoosier if you get the E-Power bc with all ecigs, you should always have backups.
Both the kGo and the E-Power have 5-click on/off features so you can turn them off and not have to worry about it firing in your pocket accidentally