Well looking at the Spikes Enhanced LPK they list the following as extras:
KNS Gen II Mod II Anti-Rotation pins
Spikes Billet Trigger Guard
Ergo Grip with Spikes Logo
ST Battle Trigger
Ambi Safety Selector
You have to decide if those extras are worth it to you. To me they're not. I don't see the need for the KNS pins in a properly manufactured lower and prefer Magpul grips over the Ergo. The DD kit includes a Magpul enhanced trigger guard, but polymer not alloy (though I don't see any problem with the polymer as it's plenty strong for this application). The trigger, (see if anyone else has experience with it but) I'm skeptical that it's a whole lot better than a good milspec. The ambi selector? Up to you.
I've bought two DD LPKs and like them. At the time they were $79 but now they're hard to find period. In fact you may have to get what you can find in stock these days. The Stag/CMT kit has worked out well for me also, as has ArmaLite's.
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together. You'll remember the quality of a gun long after you forget how much you paid for it.
US Army 1966-69, VFW Life Member, Retired Geek