I have a Spikes mid-length LE. I haven't had a lot of time to go to the range, but I've put 200 rounds through it without problems so far. Compared to the amount of rounds people put through their stuff on this site, its not a lot, but at least its something.
If I were you, I'd look at SmartGunner's custom built Daniel Defense upper deal going on right now. Here's how I'd order one:
Light Weight Mid Length Upper: $374
DD Bolt Carrier Group: $124
Magpul MOE Handguard $32
DD A1.5 Rear Sight $53
A complete DD upper for $583 is the best deal online right now. Here's the link:
http://www.smartgunner.com/DanielDefenseURG.aspx