I was sort of interested in the SDS1204X-E but I think it's a little out of my price range given that I already have a Tek 485 and a Rigol DS1054Z.
No need to update. The DS1054Z with only two channels on has the exact same sample rate, bandwidth, etc. as the Siglents.
(But more memory...)
Wrong.
Rigol have 500Msa/s simultaneously for 2 channels and 6M for both channels out from box. Option (or hacked) 12M for both ch.
Siglent have 1Gsa/s simultaneously for 2 channels and 14M for both channels.
This is because Siglent construction is 1ADC14M/2 + 1ADC14M/2 and Rigol construction is 1ADC12M/4 and hacked or purchased option 1ADC24M/4
Using all 4 channels simultaneously on
Siglent have 500MSa/s and 7M memory for all channels.
Rigol Z have 250Msa/s and 3M memory for all channels (out from box) Hacked or purchased option it have 6M for all channels.
And then, it is not only memory. (note also MSO simultaneous max 14M for every 16 channel)
And more. There is always background working waveform history buffer. There is max over 100M if all 4 channels is in use.
(example 1us/div 4 channels on and wfm length 7k. History buffer length is max 3912 waveforms. Just stop scope and you can see max 3912 previous waverforms captured with full resolution, full true ADC data and time stamps.
Lets calculate 4x7000x3912 = 109Mpoints wfm data. And this works always in bacround.
Other example. 50ns/div 4 channels on. One single wfm is 700pts. Buffer length is 4x700x29140 = 81M
THis history buffering it do all time. So, stop scope and look what just happend. Also every these wfm can measure with full resolution. All these wfm use for analyze with FFT or do other math. THis history works just behind and just with current wfm/s speed.
Other thing is fast sequence. In fast sequence mode it use just this history buffer and in this mode it can capture max 400kwfm/s speed. All these "segments" are just full acquisition resolution waveforms what cvan use just like also normal run bacround stored history buffer. For this there is same memory what in normal run background working wfm history buffer use if sequence mode is not in use.
So, how is this memory question.
And big difference is also. Rigol have 16k FFT, Siglent have 1M FFT what give superior resolution. It can try. take 60MHz signal, AM modulation, carrier level -10dBm and 1kHz modulation and 2% (yes two) modulation depth. Now take Rigol and look and measure these sidebands or try even find if they are there or not. Just, totally impossible and really far away, decades. With Siglent, still easy.
Siglent 4 channel X-E models are also fully MSO ready. For using need buy this option license and probe.
MSO LA have 16 digital channels max 1Gsa/s and max 14M / channel
Siglent 4 channel models have also max 500 points Bode Plot out from box. For use it need external Siglent AWG and for BP, scope take full control of AWG. Depending available Siglent AWG it can do BP up to 120MHz.
ok, lets run 1ms/div and 1Gsa/s (in Siglent, 14M memory length)
Input 12ns risetime and 30ns fall time 50ns pulses every 1ms
Turn measurements on. Ask rise and fall time and pulse width from Rigol...
Then open zoom window and zoom for 1ns/div for look this rising edge. Oh, with Rigol you can not, only 5ns/div
or is it even possible from 1ms/div to 5ns.
Now look zoom window trigger jitter. I do not know Rigol but Siglent well under 100ps. Oh well but with 5ns/div in Rigol perhaps impossible to even check.
Price is different but performance and features - far more different.