SSD is always much faster than HDD and for hosting there is a definite performance increase with SSD.. Other HDD hosting providers, mainly those who are reputed and mainstream, if you may notice, they all seems to be switching to SSD.

When you may need HDD hosting ?

In case your requirement is backup file server, which is not accessed in regular front or back end, and used majorly for backup, a cheap large HDD based hosting may be the option but for main website or application, SSD is much much faster !!