Ah, engineers! What is not to love about them? They get to use the guns, they have a ton of crazy weird inventions in the form of skills and most importantly, they have the monocles! The way I would describe the engineers would be as “the swiss knife” of the professions. You have a problem, they have some invention to deal with it.
The drawback of that is that it is too easy to try to pick just the cool toys and ignore other skills that would probably work better with your chosen play style. Let me use myself as a practical example of what I am talking about. I chose pretty early on that I wanted my character to primarily use a flamethrower. Simply because I just love the flamethrower that much. My problem was the other utility skills though as I was thinking of them in individual terms and coolness factor, instead of thinking how each one would complement better my choice of weaponry. I was also completely ignoring the elixirs since I was thinking, in a very misguided way, that would be more for some one who wanted to play engineers more in a support role.