I would avoid the AERO S-One hanguard at all cost! I bought a complete built upper from AERO last April, it would not shoot anything I fed it under 2MOA at 100yds (Black Hills, FGMM, Hornady VMax) and had some wild flyers. I sent the upper back to AERO twice and it would still not shoot. Took it to a buddy who knows AR's and he tore it down to rebuild it with a White Oak SPR barrel (AREA came with Ballistic Advantage barrel). During the rebuild he noticed how little clearance there was around the AERO low profile gas block and that the Cerakote was rubbed/worn off on the inside both sides of the S-One handguard (ie gas block was installed crooked by AERO twice!!). We reinstalled it and verified clearance with feeler gauges (very tedious). It is now a sub MOA shooter with the WOA barrel.
The S-One handguard has a design flaw/issue with gas block clearence and I was not impressed with AERO's CS when I contacted them about the accuracy issues, and their QC speaks for itself that they built the upper three times with the gasblock contacting the handguard. The QC manager also admitted eventually that they never actually test fired the upper at any point to confirm accuracy because they don't have a range at their facility or nearby!
My next purchased upper was a BCM 16" RECCE upper w/BCM BCG (BCM-URG-MID-16-BFH-MCMR-15). It's a chrome lined barrel and shoots about 1MOA. I'm about 600 rounds through it with zero issues. I'm getting ready to purchase another BCM upper in 300 BLK this month. Sure I probably drank the Koolaid Larry Vickers put out about BCM's QC:
I pretty much now stick with BCM or Geissele for all my AR parts needs, and White Oak Armory for my AR barrels.