I have the Mi-Pod and a Boulder Rock. Both low power refillable pod salt-nic geared devices.
The Mi-Pod sports a decent battery life, has a pull activation like the Suorin Drop, and also has a built in micro usb charging port. The Mi-Pod does also have a (very small) on/off switch that utilizes the industry standard 5 click system for powering on and off as well as having very bright and clear color indication of battery life. Pod life isn't the greatest so far based on the fact the my pods last from 1-2 fills versus the expected 5 fills, but I'm chocking that up the commercial salt nic liquid and the evil sweetners. Mi-Pods run from $35-$50 online with 2 refill pods being right around the $10 mark.
The Boulder Rock is similar is shape and size to the Juul. One of my favorite features is the fact that it features a built in full size male USB plug so no need to worry about losing proprietary charges (looking at you here Juuls) so you can simply pop the charger port cap off and plug the Boulder directly in to a wall plug or computer. In my experience the battery charges in under an hour and lasts me all day as a secondary device. I should note I can vape where I work and carry my main mod and use pods for when I'm up and moving around a lot or have a busy rush. I've been using the same pod for this for around two weeks and it's still running strong, though your mileage may vary. The Boulder uses a button fire and a non-standard 3 click on/off switch. These range from $10-$25 online, but don't pay more than $10 or $15 if you can help it. A 2 pack of pods runs around $8-$10 online.
All in all if you want something easy and reliable the Mi-Pod is pretty great. I do have a thing for pull activation versus button fire so maybe I'm a little biased here. The Boulder was a one-off I got because hey it was $10 and I figured what the hell. It doesn't hit nearly as hard as the Mi-Pod does but it will get the job done if necessary.