I've had poor luck with most portables. The original Pax was decent but stopped working shortly after its warranty ended. I had various cheap ones from local shops. I also had a launchbox which was ok but also broke pretty quickly.
Now as for "desktop" vapes. I have had an original (non digital) Volcano for years with just a few problems. I did have to send it back once to get fixed as it would just heat up to top level regardless of the knob settings. I also had some issues with the switches for the fan, but they are cheap toggle switches that I was able to buy on amazon for a couple $ and replace myself (twice in 5 or so years).
I hope to get a portable of some kind when the volcano eventually dies. Might go with a Crafty or a Mighty from the same company that makes the volcano (STORZ & BICKEL)