Getting contracts is slow. You might designate 1TB of space for use, but only get a slow consumption of that space over time. I have some drives that have 600GB actually being used, but that took several months. The payouts are decreasing over time as well. The average payout per GB is a tiny fraction of what it was several months ago. You can easily double the size of storage being used and still get less of a payout from the previous month.
Not sure of the future, but I split my drive space between Storj and Burst. As Storj shards begin to fill, I expand their size from the Burst pool.