If you are at all interested in building your own M4 style carbine instead of buying one 'off the rack', I'll give you a rundown on mine.
Upper is High Standard with M4 feed ramp cuts, port cover and forward assist from Prairie River, Springs from Brownells.
Bolt is from Colt and the bolt carrier is High Standard, Charging handle is from Prairie River also.
Don't know who Prairie River is?
This is the subcontractor that makes the Mil-Spec small stuff for people such as Colt and FN.
Barrel is Bushmaster 14.5" 4150 steel with permanent Phantom suppressor, 1-7" twist, 5.56 chamber, chrome lined, M4 feed ramped barrel extension.
Front sight tower is not F marked but regulates just fine with the upper.
M4 double shield handguards, I also have a Knights Armament KAC RAS railed handguard and a Midwest Industires two piece non float rail guard too but rarely use them.
Lower is a Double Star, parts are all from my bins and not sure from whom they came.
I originally had an M4 style stock from Double Star on the rifle and have since switched to a Magpul CTR on a mil-spec diameter VLTOR extension tube, the buffer is an H marked Colt and the spring is from Brownells.
The pistol grip in the picture is a straight mil-spec A2 but it was changed out for a Buffer-Tech TangoDown grip and this is being replaced with a Magpul MOE grip.
I have a low profile single point sling mount at the front of the extension tube which is use with a CSM Gear single point sling.
I also use a Vickers two point with this rifle, depending on my mood.
The back up iron sight is a Matech and the scope is a TA101NSN ACOG on a GG&G quick release mount.
Magazines are Brownells Mil-Spec or Magpul P-Mags, again, depending on my mood.
Toatl cost of my build is scary, over two grand with the change outs and optics but the rifle runs flawlessly.
Best accuracy is obtained with Black Hills 77 grain Sierra load when I can get it.
I hope this allows you to consider some other options.
If you only buy once, then buy exactly to your specifications.