I absolutely LOVE the Pax Era! I've only owned mine for about a month now but it's been, by far, the best prefilled cartridge vape pen I've owned. I had numerous problems with 510 cartridges, from them leaking to them either not working flat out or the coil burning out a few puffs in and I dont like buying disposable vape pen because i feel they're a waste of technology/resources so when I saw this I had to try it (bought it blind, knowing nothing about the product.) Terrapin Care Station has Keef Cola brand Pax Era pods for $35 plus tax which helped sell me on buying one (cuz $45-70 is stupid expensive IMO) and so far they work fairly well. I dont get MASSIVE hits off of the Era but I DO get a hit every time, one I can actually feel in my throat/lungs and gets me buzzed (aka they have more "potency" to an IMO.) I like to puff on the Era (I.e. take multiple hits in a row) which is where the Era falters IMO. After 4-5 good hits, in my experience, the coil or battery seems to start to overheat (or something) and the resulting hits are weaker then the previous ones. When that starts happening I let it rest for a bit (or trade out cartridges.) As for the catridges themselves i havent had any bad ones yet, though it's probably just a matter of time. I do like the design of the cartridges/battery, I hated interchanging the 510 ones so the fact they just slid in and out and work automatically upon insertion is a HUGE plus in my book. The battery itself is nice and solid though short lived (I carry a charger with me at all times/keep my Era charged because I'm an all-day smoker/vaper.) My only major complaint (as with my Pax 3) is the Bluetooth in it. A majority of the time I struggle to get my Pax(s) to connect to my phone via Bluetooth (as in it either won't sync to my phone or if it does sync the app doesn't recognize the Pax [and yes I have everything properly set-up/turned on.]) Other then that, I have no complaints about the Pax Era.