I've never heard anything bad about them from people I know that know how to run equipment.
VFL 400.1 - 18 months straight in a daily at 0.5 ohm running down to 9V without any issues (not recommended)
VFL 1000.1 - 9 months straight daily at 0.7 ohm (0.35 to each 500.1 inside) with no issues
VFL 500.1 - 4 years off and on in a daily at 0.25 ohm with occasional overheats from FL temps
VFL 100.1 - 3 months daily at 0.33 ohm with no issues
VFL 750.1 - 2 years in a burp car at 0.1 ohm with no issues
That's all people I personally know or myself (I own 2 AB 1000.1).
I used to have that walled Challenger, then it got totaled...
2015 IASCA Welterweight Champion and Record Holder - 156.0 Avg (No door blockers)
2016 IASCA Welterweight Record Holder - 157.7 Avg (Door blockers used)
Team Sundown Audio & Fullriver Faction Member