Pros, it might be more accurate for you. Cons, it's slightly heavier and bulkier and could fail and requires a suitable holster.
Weight-wise these are incredibly light. The original Trijicon RMR seems a bit bulky, but the newer 'micro' RDS's (Shield RMSc, Sig Romeo Zero, etc.) are tiny. Co-witness iron sights are a good idea with any electronic sight, in case of a failure. Finding a suitable holster 'was' an issue early on, now it seems 'most' maker's have that covered.
I would say that the biggest con is you really need to put in the time to ensure you can reliably pick up the dot when you present. That's really more of a consideration than a con in actuality.
With irons that co-witness, I don't think this is a problem. However, I had one on a pistol that had no iron sights (a Ruger 22LR pistol) and even finding the dot was difficult when first starting out.
Regarding more accurate, I just had one out on a 22LR pistol yesterday, With all of the years practice I've had with iron sights... it's rather disappointing how much better I can shoot with a Micro red dot.
YMMV,
Jerry
