I use a Streamlight TLR-1s on my nightstand Beretta. I will always have a railed nightstand pistol with a light on it.
Tactical disadvantages of a light source are not worth considering compared to accidentally shooting a friend or family member. I'd rather die than do that, easily.
I do acknowledge that a separate handheld light alleviates the risk of muzzle sweeping people, but I don't trust myself to fumble for two separate objects with separate control interfaces woken from sleep at 3AM. By just worrying about the pistol I can keep 100% focused on trigger discipline.
As for the balance issue...just make sure you get practice time with the light mounted, just like you'd practice with a new carry load.