HVAC System replacement

[Gp G.]

A big hvac company technician visited my rental unit. He says the furnace is broken and the evaporator is completely choked. He suggested tenants not to turn on the thermostat any more as it may cause fire and carbon monoxide etc.  issues. He is Suggesting replacement of the whole new system. He says the base price to replace them starts around 11k for the carrier system. About 3 months back I replaced the whole system for around 6.5k for a similar size 2.5 ton system from goodman using a contractor from a small company. But this big company hvac technician says goodman is bad but small company technician says goodman is good. Big company technicians say lifetime warranty (also 5 million insurance in case of fire) they offer and inspect every year once for free. But for me 6.5k vs 11k means almost double the charge. Any pros and cons vs big hvac company vs small company.