The big difference between the two models is the purity of the AC signal. Regular gennys make your standard 1 phase 120v AC. Usually good enough to power your TT. Some people would gawk at the idea of powering up sensitive computer devices such as laptops to this type of power. I think it's fine and do it myself with surge protectors.
A most simple explanation of the inverter genny's: produce 3 phase AC power and take those three phases to create a strong DC voltage that feed into an inverter. The inverter takes that DC voltage and creates a super clean distortion free single phase capable of powering sensitive devices. They are typically quieter than your average genny, lighter, and produce less power per cubic inch of the frame it is contained within. Much more technology involved in the inverter, so more money to purchase.
I've got both. I take the 4000w champion genny out when the rooftop AC is required. It's got wheels and a handle. It ways obout 130 pounds filled with 5 gallons of fuel. Technically I can lift it out of my truck, set it on the ground and roll it, but it's much easier with 2 people. The Inverter weighs about 50 pounds. Carrying handle. Only holds about a gallon of fuel. Super easy for me to manuever around myself. And much quieter than the regular genny. But doesn't have enough guts to power the rooftop AC unless I buy two of them and run them in parallel. Aint happening. I've got a couple batteries and 2 100 watt solar panels, so I've got plenty of power.