Which will last longer in a laptop, HDD or SSD?

We are about to renew the laptops that our field based network engineers use to configure our customers Cisco switches and routers when on site. Should we use rotating media (HDD) or solid state media (SSD) based laptops? There are about 100 field engineers and May 2017 is when we intend to do the renewal. High performance is not needed as they are only copying a router config (about 4Kb) over 9600 baud. They also use the laptops for email and web browsing of course.

In the past I have suggested that HDD based laptops are cheaper to use over a 5 year period than SSD based laptops but that was before 3D TLC SSDs were available. My network engineer colleague suggests sticking to HDDs because they are slightly cheaper to buy and he points out that when switched off the heads are parked  so no damage can be done if they are dropped. I think that SSDs may have advanced in reliability over the years so that in the long run SSD based laptops may be cheaper to maintain than HDD based ones. Please bear in mind that most of the cost of a failed "disk" is a network engineer off the road for a day and $50 shipment for the replacement to be sent to him via courier.

So anyway which should we buy and why? The laptop body and screens cost the same whether we put SSDs or HDDs in them.