I love it and wish it came in colors. I originally got it for outdoor activities like hiking, boating, etc. since it's so pocket friendly but since then I've ended up using it everyday because it's so easy to keep in my purse. I've never used the carto in it but use the extension all the time with cheapie Bauhway LR clearo's. The Nano clearos fit perfectly inside too. It's a great little stealth vape. I've been using mine for 8 months now and it's been abused. I really need to get a backup. I get a full day out of 18350's. I found a number of sites that talked about modding it further.
I guess it all depends on your needs and purpose.