Upsides : Price, power output.
No UL approval certification
No FCC approval certification
No CSA approval certification
Questionable CE certification? Could be just a fake silkscreen ( hey, it IS China )
If it is found to have caused a fire, who will be on the hook? Food for thought.
Question for Notnyt: did you match the gain to the gain of the Marathon 5050 when you say that the new amp has 6 db more output?
Ask your doctor if DIY is right for you. Side effects of DIY may include anxiety, elevated blood pressure, lightheadedness, rapid heartbeat, skeletal muscle flaccidity, euphoria, psychological dependence, insomnia, confusion, blurred vision, impulsivity, uncontrolled or repeated movements.