I prefer the electronic voltage regulated mods simply due to the fact that they put out a consistent amount of current throughout the charge cycle of the battery.
So even at 3.3V remaining on the battery, the booster circuit in a voltage regulated VV device set to 5V will give you 5V...
On a mechanical mod, the voltage will drop as the battery drops... So you will see pretty hot vaping initially, and it will get cooler and cooler as the battery discharges.
You also don't get the safety features that an electronic mod offers, like reverse battery detection, low resistance / short detection, low voltage detection, etc.
And lastly, there is a potential to deep cycle your batteries on a mechanical mod, that a well programmed electronic mod can avoid... The electronic mods will usually cut themselves off at somewhere around 3.2V... So you don't fully deplete the cell.
All that said, with few exception the electronic mods out there all look pretty bland to me... All the artistry and craftsmanship goes into nice mechanical mods.
So there is certainly a market for both.
I'm a tech geek though, so until I see a mechanical mod that I just can't live without, I'll always go for electronic over mechanical... Main reason being the safety features and consistent vape experience.