THere is a never ending debate on which case is better; is all a matter of what you are looking in a case.
I have two choices in terms of case choices; I do not have either, so that will make me somewhat unbiased in my opinion.
In the HARD CASE corner, I have the Pelican Tactical Case (1700):
The case case has a MIL C-4150J (Military Standard) and an IP-67 (Ingress Protection) Certification; making the case certified for military use by the US military and by NATO.
The Case is certified by the ATA (Air Transportation Association) for Airline transport use, so you can use it to travel with your AR15 around the country (as long as the rifle is stored in the cargo hull).
It is watertight, neutrally buoyant (it'll float for those of you in Rio Linda) and will take a beating without damaging the contents (say, knock the zero out of your rifle scope).
The 1700 is a good for an AR-15 (16 inch) and the 1600 is good if you choose to break the rifle down in two parts to save space. As with all Pelican cases, if you break it, they will replace it, no questions asked.
In the SOFT CASE Corner I have the Blackhawk Industries Homeland Security Tactical Case.
The case is made of tough Cordura Nylon, removable .375 inch closed cell foam padding, full 360 degree padding, full wrap around carry handles, #9 YKK zippers with silent zipper pulls, detachable shoulder strap and HawkTex shoulder pad.
The middle of the case has two rows of BTS webbing and has fully expandable hook & loop wrap keepers for any rifle with accessories such as scopes, lights, lasers, rail mounts, etc.
The top section has an accesory compartment with Velcro that you can attach mag/accesory pouches via hook/loop fasteners.
Now, one choice people would opt for would be to have BOTH a Hard Case (for Airline Transport) and a Soft Case (for range purposes); You can have a Pelican (or similar style) as an outer case, to protect the rifle while on transport and have the soft case (like a BHI HST) as an inner case, to take the weapon from the hotel room to the range (say, you are going to the Thunder Ranch and you stay in a hotel outside oif the complex).
Again, I don't have wither product (I have a MOLLE Tactical Cae), but since the HARD/SOFT Case combo is common for the SF Guys (Part of the SOPMOD Kit), it makes sense to have something like that as well.