I have a Losi and would recommend them, we have at least half a dozen at the club.
The initial problems occured with the firmware update, the ESC themselves were not faulty and all problems were corrected very quickly by Horizon UK.
With the latest Software and firmware they perform extremely well, the motors are on par with more expensive makes.
Add the ability to adjust many of the settings of the ESC via the pc and the value for money is very hard to beat