I need some help making a decision. I'm building an 8" 300 BLK get-home pistol and can't decide whether I should go with a standard upper receiver (Aero Precision Gen 2) or the Aero Precision M4E1 Enhanced Upper. The M4E1 having a forged handguard mount seems like a neat platform, but the standard upper would be more flexible and would let me test out the Dolos Take-Down System (which I'm not quite sold on...more on that in a bit).

M4E1 Enhanced
Pros:

• Nice lock-up of upper receiver to handguard (some reviews say almost monolithic?)
• Theoretically lighter since the handguard mount isn't a separate piece and AP claims they make "additional lightening cuts to save weight and allow for more efficient cooling"
• No worries about lining up gas tube hole (seems like a minor concern)

Cons:

• Limits handguard options to only those that use the BAR barrel nut (are all of these oversized in diameter?)
  
• One-piece design of the upper means I couldn't try the Dolos, even if I decided I wanted to

So this begs the question...is the Dolos system, or even just the flexibility of a standard upper, more valuable than the benefits of the M4E1 upper? I think the Dolos is interesting in that it allows an AR to pack down to a crazy-small package when combined with a Law folding stock adapter, a benefit that seems really nice for a get-home bag. Then again, I'm not crazy about the idea of dropping a barrel assembly with exposed gas tube into the bottom of a backpack to get smashed and bent. That gas tube hanging out unprotected just seems like a major weakness to me.

Are all BAR handguards oversized (from what I've read, that's to allow suppressors to sit inside the rail). Are they obnoxiously large or just slightly different?

Help! I'm being super indecisive.

Links were putting me over the 2000 character "new account" limit in my original post.
Here they are for ease of reference:

• Aero Precision Gen 2
• Aero Precision M4E1 Enhanced Upper
• Dolos Take-Down System

Depends on what you want to use the rifle for.  To me, the quick barrel swap kits seem like a solution looking for a problem.  
I do own some Aero M4E1 and M5E1.  They are as rigid as the reviews make them out to be.  You could hit a homerun with this thing and your front sight would still be zeroed.  As far as girth, they're 2" outer diameter.  That's about the diameter of a small can of redbull.  It's not too big for my hands.

Thanks for the first hand account of your experience with the M4E1. That carries more weight with me than a lot of gun blog reviews.

The goals for this build are to have an ultra compact, light (not necessarily ultralight), PDW for a get home bag with significantly better capability than my EDC pistol.

My Aero M4E1.  I love the hand guard and the way it mounts.

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