Burstcoin seems to be vialable project with proof of capacity concept.
Using a HDD as infrastracture for the Network do not require any difficulty to deploy.
After involving in this projects i will
PROS :
Easy setup
Blockchain 2.0
Low network rates
Cross application Wallet
Marketplace
Community
Cons :
Bugs
Plotting HDD ( requires a lot of time to optimize HDD for mining )
Only 15% Burstcoins left.
Stable blockchain
If you want to try mining with HDD i would suggest to you 8 TB Seagate.
With current price you can earn up to 40$/months/ Disk
It`s not a lot but still, you have HDD which you can sell later -30%
Good Mining !