I would not use the modified sine inverters on electronic items... Too much of a risk. The pure sine wave inverters don't cost as much as they used to. With the PSW type you don't have to worry at all what you plug into them.
The PSW type inverter also don't produce as much RFI signals which is probably why the TV didnt work as well as it should have when being operated from the MSW Inverters....
I started out with just a 150WATT PSW Inverter and things worked so well I kept adding 120vAC units to the inverter and purchased a 300/400Watt PSW Inverter and finally ended up with a 600WATT PSW Inverter.
Of course Inverters like to eat up a bunch of battery power so expect to add enough battery capacity to operate your Inverter for the time period you are going to use it.
We do alot of camping off the power grid and the 600WATT PSW Inverter works very well for the things we like to do. My battery bank is a 255AH setup and I have planned it all out to have all of the 120VAC items we want to have running form our 600WATT Inverter and all of the 12VDC items we want to run direct connected to the battery bank.
The game plan for us is to run all of these items in a one day/night camping run off the batteries and then recharge the batteries the next morning with the trailer connected to my 2KW Honda Generator using a RV30A-15A long adapter. Using the trailer smart mode technology converter/charger I can re-charge my battery bank to its 90% charge state in as little as three hours of generator run time. Once charged back up to the 90% charge state I can run it down to it's 50% charge for 10-12 cycles before doing any harm to the batteries. I have to recharge my battery bank to a full 100% charge state after 10-12 cycles otherwise it will do harm to the batteries.
this makes it pretty successful for us to camp off the power grid for many days.
Here is typical trailer layout I have followed in my use of PSW Inverter.
just my thoughts
Roy Ken