Yes, we have rented several times. The more familiar that you get with Rome, the further out from the center you can go, and save money.

We stayed here once. http://www.pantheonapartment.com/

Quite expensive, but the rooms are huge. Several people can actually sleep on the couches in the living room, besides the 2 bedrooms.

Location is within a few steps of the Pantheon, and across the street from Tazza d' Oro coffee shop. Trevi and Piazza Navonna are a few minute walk in opposite directions, and it's midway between the Colliseum and Spanish Steps.

The apartments are handled by the Hotel next door, so someone is always available, and the young men spoke fluent English.