The Sigelei Zmax V3 and V5 Telescopics are fine rigs. There are a few left here (body only) before they sell out again.
Mods
Varitube is good for the Sigeleis, too.
I agree with the Sigelei Zmax. I am on my third (2 replacements) with the SVD. Switch problems and turns off by itself. I am most pleased with the Sigelei Zmax v3 and V5.
V3 and V5 share the same performance parameters, basic electronics and mechanical features. V5 has the cell phone charging accessory which attaches to the 510/eGo connector. The cell phone charger connects to the cell phone with a USB cable. The firmware for V5 is different from V3 because it has a ninth menu item for operating the cell phone charger.
Other differences between V3 and V5 are found in the OLED display. The display for V5 shows a battery symbol to indicate state of battery charge and a puff counter.
Both are fine rigs and meet different requirements for users.