those guys are all over the place. on a holley page and holy **** a lot like the sniper, others say stay away from it and spend 1200 more for the terminator and others are having a ton of issues..
Considering millions of factory 1980's era TBI EFI systems would run in excess of 200,000 miles without major failure, every aftermarket system on the market is completely unreliable in comparison.
These systems are not OEM quality, although most of the user serviceable components are OEM. The Holley Sniper EFI is by far, the most refined TBI EFI unit with the most capable software.
Everyone loves these units until they fail, most failures are at the least opportunistic time. It's not a question of if, but when will a major component stop functioning. Issues that aren't issues with carburetion, become major deadlines with EFI [RFI / EMI / Grounds / Voltage etc]. Unless the ECU is mounted inside the car and you carry a spare parts kit [ECU / Injector / Pump / TPS / CTS / IAC etc], I wouldn't consider switching to EFI.
