Are all Lower Parts kits the same? I'm not worried about the trigger I will be using a Wilson TTU Trigger.
But why are the prices all over the board like DD is way high is it that much better than Stoner or DPMS

You can ask four people that same question and get five different answers.  My take is "most" lower parts are the same.  Most companies outsource them from assorted vendors.  Trying to figure out which vendor makes which part gets confusing to say the least.  

Several will be along shorthly to extoll the virtues of one brand or another, mostly because that's what they have.

You need to ask this on m4carbine.net (m4c).
They will tell you that if you buy anything other than one of the "tier one" LPKs (or anything else for that matter) you will create a situation wherein the Universe will collapse.
And it will all be your fault.
I have two DPMS selectors/safties that I DO NOT like the feeling of; mushy clicking into place.
I have a Stag that clicks authoritatively into place and feels good.
The Stag buffer retaining pin seems, however, rather long and pointy and not one you disengage without using something to push it; using a finger hurts.
Or I might just be a wimp.
As far as pins and detents and detent springs and mag catch and pistol grip screw, probably not enough difference to make any difference.
Except on m4c, where you better pay a bunch for each and every part or the deaths of all living creatures known and unknown will be on your head.

Actually there is a difference.I can not tell you which manufacturer is better,but there is a difference.It all has to do with how some of the critical parts are made.whether or not they are stamped,laser cut or waterjet cut or are they made with MIM technology(essentially molded metal garbage)are critical surfaces heat treated etc,all parts kits are not the same.

Sooo, if you were looking to buy a lower parts kit and quality was the deciding factor what would you get

For the most part the major parts for LPK's are made by a few suppliers, irregardless of the name on the package. Where the difference comes is mostly in the finish. Some have a better overall polish and the sear/hammer engagement surfaces have a better polish. Personally I'll take a Superior lower and a DPMS LPK, polish the engagement surfaces, utilize the takeup screw in the Superior lower and get a much better trigger than is available in most any other stock combination except match or aftermarket triggers.

Good advise given.....the only thing I would add is watch out for "match" trigger setups or two stage triggers.  Of course I am partial to the standard myself....but that is me.
I have seen 2 stage triggers go FA or burst 2-3 rounds with some time and wear.  Just had a young man in the last CCA class have problem with an after market trigger go into burst because whoever made the trigger took a bit too much material off where the trigger and hammer engage.  
Also keep in mind that when folks attempt to "do it yourself trigger job" the responsibility rest on your shoulders....

Unless doing a distance gun.....stay with the standard trigger. IMHO

Romper

FYI this was a Bill Springfield trigger with only a few hundred rounds on it.....

Some good info thanks

if you're not using the fire control group, then a cheap LPK is fine.  i do this sometimes, but i always buy a set of good pins... the safety selector detent pin and take down detent pins are usually the three parts i see that are rough on the ends and work poorly.  otherwise, i always lay hte parts in and check for tolerances and function (as best you can) prior to 'permanent' installation.

$.02