I have a Vamo V3 that suffered a thread failure, I replaced the top ($6) and it's still going strong, but it helps if you're familiar with a soldering iron.
My SVD is my second one. The first failed electrically within a month after receiving it, and its replacement is sitting in my vape cabinet because the fire switch started going funky after a few weeks, and one day when I feel like it I'm going to see if I can't fix it.
That being said, there are a LOT of people on the forum that have one (or both) of these units that are still going strong after a year of vaping, so my experience may not be typical (although it does happen to others).
I would give the edge to the SVD, however, because (to me) it seems to be a bit more mechanically sturdy than the Vamo.
And not to redirect you, but at the price point/design of these two mods, have you looked at a Sigelei Zmax? I don't have one, but it seems to be a popular unit that many feel is better than either the Vamo or the SVD.