...I'm into working hard as long as that work happens between the sheets. 
I was seeing an UTR provider recently and hit session 5....then the drama began. Getting MSOG became an ordeal...she started asking for more personal details...told me way too much about herself and her boyfriend....etc etc. She's off my list from now on. No sense of discretion...and the sessions suddenly stopped being GFE.
Deal-breakers.
Being a little thick is not an issue. But, just not into BBW. Totally okay if someone else wants to hit that though. I hear the phrase...the more cushion, the better to push in. I just have a preference on the top end of that scale...and on the bottom to be honest. Too skinny can also be bad.
Size is relative.
More work? Yes. Any positions where you would take the girls full weight - standing while carrying her, and some others - are correspondingly more work. If you aren't strong enough, they might be impossible for you.
If she's taller, you might have problems reaching up to fondle her, pull her hair, etc... while in some positions, no matter how slight her build. If she's too big around, there are those limitations.
Bigger people, for the most part, are generally less flexible - though not always.
Some girls like to feel man-handled. And man-handling a larger woman convincingly is going to be correspondingly more difficult. Not sure that it matters in the "hobby" world, where people approach things differently.
Other than that, it isn't really a pro/con thing. It all comes down to what hits your buttons. The "cons" I've listed above are mostly practical limitations which might not matter to you.
The pros would just be if you like women built like that. Novelty if you never have experienced it.
I've never been with a smaller or thinner girl who wasn't "comfortable". I have been with a heavier civilian who was uncomfortably tight. Certainly a larger woman can be great in the sack - but no matter what her skills or enthusiasm, if you aren't into a girl - you aren't into her. Same with anything else.
