I own both of those.
The Vamo 3's 510 threading failed after about a month or two, I bought a replacement stainless steel top cap, soldered the wires to it, and it's been going strong since then.
My first SVD had an electrical failure after a month. I attempted to unlock it (holding the + and - buttons down together) and a puff of acrid smoke came out of it, and it stopped working. I sent it back and got a replacement.
A month in, and the fire button started getting wonky, Not firing every time unless you pushed it "just so", and random shutdowns. It now sits on a shelf in my vape cabinet, on the injured reserve list until the day I feel like taking it apart and seeing what's up (not worth it to me to send it back again, just to get another lemon).
I know it's a little more money, but in the same performance class, I'd go with a Sigelei Zmax.