Is there a price yet? Otherwise there's really no way of comparing.
Given it's 1GHz max bandwidth, do I assume that 4GSa/s is per channel?
Not yet overseas price.
But if look domestic price it give something for thinking.
SDS2000 series starting around CNY6000 and SDS3000 starting around CNY 20000.
I do not believe simultaneous 4GSa/s for all channels.
This is what I think after read chinese datasheet etc.
It is organized so that 2 channel group have 4GSa/s (for single channel in use in two channel group 4GSa/s and for both channels in use 2GSa/s per channel. In 4 channel model there is 2 x 2channel group.
(in 100 MHz model 2GSa/s arranged as in SDS2000)
If this is true then 4 channel model can use with 2 channel so that both have 4GSa/s.
Of course real time work need least 4GSa/s for 1GHz BW.
For repetitive signals this is not at all problem when use repetitive sampling.
So, it is not fully 1GHz real time oscilloscope if all available channels are used simultaneously.
Analog channel before ADC is designed for 1GHz BW. Risetime better or equal 350ps.