As an insert owner, I wish I didn't get an insert.
It sounded good at the time, and wouldn't take up any other space.
and then the power went out for 5 days and I no longer had a fireplace to burn wood.
Consider a free-standing unit. They are easier to clean, usually cheaper, and you don't lose access to your fireplace if you have to.
I have a generator that I can fire up to power our furnace in the event of an outtage (which is likely in our area).. so I'm not too concerned w/ that... and space is at a premium in our house... I wouldn't even bea able to find a place to put it... Our fireplace sits dormant and we have not used it in the 3+ years we've been in the house... which is why I think this makes the most sense for us