Solid-State Hard Drives attempt to combine the best of both worlds between SSDs and HDDs. SSDs offer huge performance increases, but can be extremely expensive. Traditional HDDs have much larger storage capacities at a friendlier price point, but aren’t as fast. So SSHDs utilize an SSD cache, usually around 8GB, on which the drive places most frequently used files, and then utilizes the larger spinning-disk storage capacity for the rest of your data. One of the reasons that some people don’t find them effective enough is they think the SSD cache is too small. Hopefully with the progress of time, demand, and technological advances, in the future these SSD cache portions will be larger without becoming excessively pricey.
SSHDs are something that you're going to see a spectrum of anecdotal experience on, some people have said they feel like there's negligible benefit to them, others feel like they're fantastic at increasing performance.
The general consensus, from reading through others' experiences on the matter, is that the biggest benefit to them is if you're really into open-world type gaming, there can be a considerable decrease in load-times, particularly when moving into/loading new areas of open-world maps. They can also decrease loading times for important things like your OS. Some people prefer this, while others you'll find prefer using a traditional HDD and an SSD.
Ultimately, it's going to come down to where on the price-vs-performance slider your priorities land.
