Feel free to dm me to set up time if you want more beyond the rambling answer below Peter S. ...
High-level my pros/cons vary pending the season.
Right now I'm at/slightly above the capacity I want (I also am a dedicated parent + triathlete so like to carve out time to be my best at both of those – one of the reasons I love this type of work) and feeling confident about how I can make an impact at high-growth orgs, ability to do the projects and work I like the best, my cash flow, etc. My other major pro for fCMO'ing is being 'above the fray' and out of the politics. I'm a very transparent person and while that can sometimes burn you inhouse, it's more often appreciated as an outsider.
One of the biggest cons is time to do biz dev/not always in control of capacity due to macroeconomic trends/people undercutting pricing/getting connected to roles that are out there, etc. which can also happen searching for a 'forever job' so it's ultimately it's deciding which path is more fulfilling to you because there is no wrong way – except (my opinion) having feet in both sides. It makes it really hard to commit to a project or a company if you are constantly looking for greener grass.
Obviously there is a lot behind each pro and con so happy to expound.