User blog comment:Silicon Soldier/Xûr's Inventory: August 21, 2015 - August 23, 2015/@comment-26625664-20150822031126/@comment-25916964-20150825031244

The exclusives on offer are a Shader (called the "Old Guard"), Sparrow (called the "S-34 Ravensteel"), a player Emblem (called "Be Brave") and a Brave Ghost Shell. These look to be a part of a pack called the "Founder's Fortune Pack". From what I've gleamed, preordering gets you this pack, but only if your already over light level 30, or have both exapansions already, before 31st August.

More here (https://youtu.be/Jpi-uWDF_Z8)

When it comes to the new DLC, that will just get you the new story missions, strikes, gear, etc. (plus some more things). The Destiny 2.0 overhaul comes to everyone.

So it basically comes down to if you want the exclusives or not. I personally wouldn't care, although Ghost Shells have buffs now so...