The 3 major things you need to consider when it comes to buying any hard drive or SSD are:
- How am I going to back this much storage up
Now, Performance is especially important for video teams. If you can go SSD, do it, you're almost always better off with less capacity and more performance, which is usually going to happen with SSD.
IF you are putting together a RAID for shared editing and you can't go SSD, just absolutely make sure both your drives and RAID controller are 12G SAS.
Capacity is simple, more, more, more! You will always be better off with more storage AS LONG AS (caveat) as you can back it up, which brings us to our final factor. Back up.
Make sure you don't get so much capacity you can't, or won't back it up. Drives fail, files get lost, back up is critical. One of the biggest mistakes people make (which is really easy to do) is to get a whole bunch of storage and put all of your eggs in 1 basket.
Stay safe out there and enjoy the fact that 16TB hard drives and 8TB SSDs actually exist and are affordable, that's awesome!