Although Rails is very reasonable with its mappings and they are easy to use directly, I prefer Rails for db manipulaton, it is usually much easier and faster to type 'User.find(1).favorites << Product.find(10)' than an equivalent SQL.
Very true, but I've found that it's easy for those ActiveRecord abstractions to kill performance (I did this on a dashboard that was performing some serious calculations across hundreds of millions of records, often joining other similarly sized tables)
