Is Warlock a dip only class in general?

[Mr.Spastic]

And that is exactly the reason that dipping Warlock is so popular. You get most of their good stuff in 2-3 levels. Everything after that is weaker than if you would just multiclass something else, like sorcerer.

Just because it is weaker doesn't make it bad. Sure, you won't have the same power as the multiclass into sorcerer. Nobody is trying to argue that. The point that we are trying to get across is that they are not bad just because you can make something stronger by multiclassing. They have many things that still make them viable and fun at higher levels. Warlocks are the weird quirky character with a lot of fun stuff that you can completely miss out on if you just dismiss them past level 3.

Edit: We get why it's popular, that's not the point of the thread. The point is to discuss the merits of staying a single class Warlock or only dipping. Which some of us are actually doing and backing up with evidence.