I wouldn't touch a Toshiba HDD unless it was free. Toshiba SSD's are pretty good, HDD's have awful reliability, I would suggest waiting for WD to bring out its 5TB WD Red, thats what I am doing.
From Wikki of hitachi,
On March 8, 2012, Western Digital (WD) acquired Hitachi Global Storage Technologies for $3.9 billion in cash and 25 million shares of WD common stock valued at approximately $0.9 billion. The deal resulted in Hitachi, Ltd. owning approximately 10 percent of WD shares outstanding, and reserving the right to designate two individuals to the board of directors of WD. It was agreed that WD would operate with WD Technologies and HGST as wholly owned subsidiaries and they would compete in the marketplace with separate brands and product lines.
To address the requirements of regulatory agencies, in May 2012 WD divested to Toshiba assets that enabled Toshiba to manufacture and sell 3.5-inch hard drives for the desktop and consumer electronics markets
From Anantech Western Digital To Sell Hitachi's 3.5” Hard Drive Business To Toshiba, Complete Hitachi Buyout
Western Digital will be allowed to acquire Hitachi’s 2.5” and SSD businesses, but not the 3.5” business. Instead Western Digital will be selling that business to Toshiba – factories and all – along with granting licenses for the necessary patents, which would allow Toshiba to effectively continue in the 3.5” market from where Hitachi left off.