What makes a good rental

[Vika Bha]

Hi everyone,

I am considering buying a condo in a Boston suburb which I plan to rent out after I move out in a few years. I am wondering which would be the best option for long term renters

Just a little info about the condo. They do allow renting, and they are all 2 or 3 bedrooms. Most people who live there buy a 2 bedroom because the 2 bedrooms come with an office room and loft. People convert these into 3 bedrooms and this is known by almost everyone in the town and local realtors.
So, which would be the best rental? The three bedroom or the two bedroom? The two bedroom has a loft and an extra den which is large and can be another bedroom. They all have basements. 
thank you for your help