There will be 6 adults traveling to Rome for 10 days around Easter time. Knowing this is a very busy time, we are looking now for lodging.

I have found 3 apartment rental websites:

sleepinitaly.com
apartmentsrome.com
rentalsinrome.com

Can anyone describe how to evaluate these websites, or specifically how to evaluate the individual apartments within? Unlike hotels, there's no tripadvisor to offer detailed reviews. I also want to assure that these websites are reputable since money will be exchanging hands.

I am seeing rates of 100-300 euro per night for 6 people, which is clearly a better deal than 2 or 3 hotel rooms.

I have also heard about certain convents that rent rooms, but can't find any links to a website - anyone have any experience with this?