In terms of heat output the Velociraptor will pawn the SSD..who needs a room heater when you have the Velociraptor
In short SSD > HDD

Enterprise servers with a lot of read and write will be using the more expensive SLC memory that has greater durability..
For consumer I don't think you will be sane enough to max out 50GB/day..

If you're so worried about the read and write speed just get the latest SSD with the SF-2000 memory controllers..it'll be so fast it makes you look slow
No point getting a VR RAID 0 or a previous gen SSD RAID 0..a VR on RAID consumes more power and heat while a SSD on RAID don't support TRIM