You still have to assemble it all yourself, so I have a hard time seeing what's so difficult about buying from more than one source. You have two cardboard boxes to dispose of?
The only option where buying a package really makes sense to me is if you buy the DGX package for 299, because that's such a good deal. If you don't want that, why not pay 250 for a high quality wing, then 75 for a backplate, 15 dollars for webbing, 30 bucks for cam straps and 10 dollars for assorted hardware? It's still sub 400 dollars...why does it being sold as a "package" matter?
Some people are conscious about transportation issues such as having $20 of webbing flown and trucked across the country. In some cases there is a minimum amount to get free shipping so, shopping around for the best deal on individual components may not be the best final price to acquire the items to build a setup. Still others, especially those new to BP/W can be overwhelmed by the choices out there, and the reality is that although their is a spectrum of quality, features, etc, there is little difference along that spectrum between most makes and models. I have Edge-Hog and Dive Rite back plate, wings, and harnesses in my garage, both brands seem to me of excellent quality and I would recommend both. DGX is basically a house brand of Dive Rite. DSS makes great stuff but the shell of their wings cannot be opened. Mares has some great stuff as well, so does Tecline, Sopras Sub, etc. There is also compatibility concerns when mixing and matching....will the wing line up with the plate properly? For those who want to spend time and energy researching this, great! But some people don't want to be bothered, and their resources (time, money, etc) are better spent purchasing a complete package where all this is already worked out and they can invest their time in other things like blowing bubbles.
My reasons for going with a BP/W was that I wanted the following:
1. Durability - rugged and long lasting
3. Simplicity - uncluttered by useless, or senseless features, but easily customizable to meet my needs even if they change.
2. Ability to replace components so that the entire system is not garbage should one component fail like it did on my last jacket style BC.
For me this means that a wing with a sewn in bladder is out, even though there are other features of the DSS wings that I like.
It also means that wings like the DRIS mirage wing is out too, as I don't see a need for an STA when using 2 tank straps, but the mirage requires an STA because there are no slots for tanks straps. Which is funny because most folks will recommend the smaller lift wing for travel due to its "lighter weight" and smaller packable foot print...but that just becomes bunk when you have to add an STA to your bag. Just saying.
To me an STA is a solution for a problem that existed before tanks strap slots were added to back plates, and or for those folks who switch frequently between a double tank and single tank setup. If one's known requirement is just single tank diving then there is no reason to buy and use an STA unless your gear configuration demands that you do...but this is avoidable.
The HOG wings have built in tank stabilizers. The Dive Rite wings do not, but I have never experienced a tank move around once I have strapped it in place to my back plate, and I have used 12L, 15L, and 18L tanks.
-Z