@Alan'svapes, with the Jackaroo you would need an external charger that can charge 21700 batteries. As unfortunately or fortunately it has no onboard charging, but it does have a hidden micro USB port for upgrading the mod.
Vsticking VK530 is an interesting mod, uses a high end chipset made by YiHi. And TC on YiHi chipset is good.
CigaBuy
And if you want some really wild ideas, have you heard anything much about Squonk mods and Squonking?
It's where you use an RDA (Rebuildable Dripping Atomiser) with a BF Squonk pin and a Squonk mod with a liquid feed bottle and some plumbing to force liquid up through the 510 connector and the BF pin and into the RDA.
As coiling and wicking an RDA is much easier and forgiving than an RTA (Rebuildable Tank Atomiser).
Two of the most interesting mods on the market there are the Lost Vape Drone Evolv DNA250C (has a leaking issue that you can fix easily) and the Dovpo Topside Carbon with undisclosed YiHi chipset (still waiting for retail release, as it's just being shown off at expos).
YiHi chips seem to be up there with DNA chips as some of the best. The VK530 looks a bit strange but could be a good option within my budget.
I've read a bit about squonking but don't think I'm ready to go for a rda squonk mod yet. That may be my next purchase down the road. I like the idea of them and the Vandy Vape ones look nice. Once I invest in batteries and a charger buying a squonk mod won't be that much extra later on. The lost Vape Drone is out of my budget for now but looks nice.