Need Inverter and Battery help

Is sine wave really that important? I've seen conflicting opinions online about it for home use or even PCs, saying that it's only really needed for medical or lab equipment.

I decided to go with a simulated sine wave line-interractive UPS instead for my pc as line-interractive seemed more important?. Did I make a mistake?
It is highly recommended to get pure sinewave inverter for PC & other expensive electronics, not like the cost difference is too much to skip this. The output is considered cleaner but simulated sine wave will likely run fine provided the switch over time is low enough.

My friend almost purchased a Luminous 2400VA inverter but it was just not able to do the switch over fast enough for his LG C3 TV (it took over the PC load while gaming just fine). The seller later brought an Exide inverter (2000+ VA) which worked as expected.
 
My friend almost purchased a Luminous 2400VA inverter but it was just not able to do the switch over fast enough for his LG C3 TV (it took over the PC load while gaming just fine). The seller later brought an Exide inverter (2000+ VA) which worked as expected.
So the Luminous which he bought is not pure sinwave?
 
It is highly recommended to get pure sinewave inverter for PC & other expensive electronics, not like the cost difference is too much to skip this. The output is considered cleaner but simulated sine wave will likely run fine provided the switch over time is low enough.

My friend almost purchased a Luminous 2400VA inverter but it was just not able to do the switch over fast enough for his LG C3 TV (it took over the PC load while gaming just fine). The seller later brought an Exide inverter (2000+ VA) which worked as expected.
The inverter I chose is the APC BX2000UXI. I chose this because the switchover time seemed faster than most inverters I found and it was a line-interractive one, so I'm hoping it's fine.
 
So the Luminous which he bought is not pure sinwave?
It was, but response time was not low enough.
The inverter I chose is the APC BX2000UXI. I chose this because the switchover time seemed faster than most inverters I found and it was a line-interractive one, so I'm hoping it's fine.
Exide & Luminous pure sinewave ones cost similar. But they need 2x batteries, not sure of APC one.
 
Can anyone please provide long term review of Luminous Optimus 1250? I current have a Microtek UPS SEBZ 850 VA which we bought years ago but recently around 3-4 years ago the original PCB got fried somehow and replacement PCB again got friend this last summer. Also the switchover time with new PCB is noticeably worse than original PCB. Are Luminous original spare parts easily available in long term (considering the fact that an inverter is used for quite some time)?

I am planning to get 260Ah battery (Exide IT950) to use with Optimus 1250...