I think they're actually talking about other items being the bottleneck as opposed to the rate at which you can grab information off of disks, so if you have an

I think they're actually talking about other items being the bottleneck as opposed to the rate at which you can grab information off of disks, so if you have any meaningful fraction of your data being hot at any one point there is no advantage between either. Even with HDDs, if you actually want to use all your throughput you're likely going to have problems with the bus (rarely needs to be optimised in 99% of cases) vs the drives (needs to be optimised in all environments).