I am looking at purchasing another tube for a new 9mm project.  These 2 brands seem  to have a lot in common and the DD rail appears to be of the same quality as the KAC.  Right now I own one KAC Ras system on my m4 and am very pleased with it.  The DD system looks virtually the same and is the same price.  They havent been out that long for lots of data and reviews of the product so I was wondering if anyone had any input as to why I should choose one over the other.  I am sure either way i will be happy.

This was discussed in another post, I can't remember where.

The 2 main differences that I recall were:
1) Weight, the DD is lighter.
2) Shape, the DD has a "flat" bottom.  The cross section is not circular like the KAC.

I would go for the DD (like I had the money).

One difference between the two is the DD uses and aluminium barrel nut while the KAC uses a steel one.  That is where the weight savings comes from.

I haven't gotten my grubby little mits on a DD hand guard yet but I'm going to get one as soon as I pick up a mid-length upper.  It's rumored that they are going to start offering a complete upper with their hand guard system installed sometime soon.  From what I hear it will be the first mid-length, 1:7 twist, 4150, extended feed ramp upper available!

I've exchanged several dozen emails with the folks at DD and they've answered everyone of them in a polite, professional manner.  They seem like great people and a great company so I'll be giving them some of my business.  Who am I kidding, I give everyone my business [;)]  

With KAC rail covers in place the DD forend has a simmilar shape to the oblong M4 fat handguards.  They are very comfortable but since almost everybody seems to be using a vert grip these days I guess it does not matter that much.

You really can't go wrong with either...I just put a DD 9.0 midlength tube on a midlength project that I was doing and I'm really impressed at weight savings of the Daniel Defense tube...It gave the rifle a light well balanced feel....

The DD tube as inkabe mentioned is more oval shaped and feels like the M4 handguard, where the RAS is round.

I've got the RAS on 4 of my guns and I'm in the process of getting a RAS FF installed on my Colt M4....I have handled and shot numerous guns with the RAS FF....

You really can't go wrong with either product...

Forgot to add, here is a link to some of the projects that I've been doing, it has numerous pics of the Daniel Defense Mid Length tube on the page:

[url]http://www.coloradoshooting.org/usmc03.htm[/url]