I fell into the lesser priced ecig market when I first started vaping. "Why pay $160 plus batteries for a variable voltage PV", I asked myself. I spent $35 for a 510 kit, $50 for an eGo, and almost that for a Riva kit. I tried atomizers, cartomizers, tanks of all kinds, and still didn't find the ecig of my dreams. I probably spent well over $200 chasing the low priced winner.
One day, I realized that I spent about $180 a month on cigarettes (and I live in a low priced area for tobacco). Suddenly, it dawned on me that I could spend that much one time for a really high quality mod and maybe end the chase.
So, I dusted off the credit card and ordered a Satin Provari and 4 18650 batteries. I already had a Trustfire charger for the batteries. The Provari came in and I popped a 3 ohm cart on it. Once I played around with voltages, I found that even a .1 volt change in voltage was detectable in the vape. I could tell a difference between 3.7v. 3.8v, and 3.9v.
I wondered how accurate this thing was, so I screwed on my inline digital voltmeter (about $15 from vendors) and installed my 3 ohm carto on the end. When set at 4v, the digital meter read 3.99v. Cool! I changed the carto to a 1.5 ohm and vaped. The DMM still read 3.99v. Really cool!
You get quality and stability in a higher priced mod and to me it's worth the money, especially if you use the money you would have spent on cigarettes to purchase it. It's a no brainer once you think about it in those terms.
ETA: It's made completely of stainless steel, so you don't have to worry about the atomizer threads wearing out. My eGo's got a little sloppy after a couple of years of screwing and unscrewing cartos. If you drop it on concrete, chances are you will have to look really hard to tell where it struck the concrete. Stainless steel is tough stuff. 18650 batteries cost about $5 each and they last forever. I'm 8 months into rotating 4 of them with no signs of fatigue at all. After multiple drops and rolls on the driveway, my Provari still looks new. There is one tiny scuff that you can see if you hold it just right in the light and rotate it back and forth.