I was reading this article about tips & tricks for Bootstrap 3 and it has a trick for a hover dropdown (so you don't have to click before a menu pops up).
Should I enable this? Is it generally found annoying or something else?
Depends a lot on which kind of thing you work on.
For example if it is primarilly targeted on mobile, do not enable dropdowns on hover. On the other hand, in case your thing is a desktop application and you have a strong reason (like complexity, lack of mobile users, speed of use, enough hit area in design etc. ) - go for it.
When taking a Mobile First approach, your navigation would be determined by your product being used on a phone. If this is the case, drop downs would be a poor choice. Not only do hover States not exist in mobile, but they increase complexity (typically unnecessarily). This scales to desktop where ideally you would share the same navigation hierarchy -without drop downs.
If you're looking at strictly desktop, hover effects are still very valid, and could be a useful tool. However, if in the future there is potential for mobility, it still might be prudent to look at other, simpler navigation options.
Finally, if a client is requesting complex navigation systems, it's our duty as UXD to inform them of the potential pitfalls of such choices, and help guide them in a more paired-down direction.
There's an option to keep both. Some users will find it very useful to have a hover feature, especially on a desktop.
While for the others, mainly the touch screen users - You can make the following adjustments in your CSS: https://stackoverflow.com/questions/2851663/how-do-i-simulate-a-hover-with-a-touch-in-touch-enabled-browsers