You are correct.
The MIDI implementation in regards to controlling the FX is extensive!
As an example, you can load any of the FX and change values on the fly that you cannot see or touch at once; like on effect 1, page 1 and page 2 simultaneously from OT/Force/Whatever.
This works for bus and input fx.
In my experience the SP midi cc sequencing is buggy though. I ran into all sorts of issues when trying to specify an effect and alter the parameters from my Syntakt. It would sometimes not activate on the first loop of a pattern, as if there were glitches with the midi transfer (or more likely a glitch in the SP’s processing of the data).
Do you also send clock ?
I have an SP-404 MKII and MPC One alongside my Syntakt.
In theory and having watched several YT Videos, SP & ST seemed like the perfect match for me.
But it turned out to be cumbersome triggering the right pads on the SP.
I made a table to have an easier overview, but it still did not become what I expected.
I also used the effects on the SP rarely and sample management really is a PITA (if course I tested SP Software, but only being able to move a single sample at once to another pad is ridiculous) which is why I have it for sale now. MPC pairs nicely in both directions with the ST, but honestly I am secretly leaning towards a DT for that very fast sample mangling, using LFOs and all that Elektron magic 
I had a similar experience. It just was never really simple and fun to pair them up.
I’m actually not sure but I think so. Does it make a difference in this case?
It adds midi data transfert. I’d compare with clock and without it.
Digitakt, mono samples but great at sequencing mono lines on outboard gear like my Jupiter Xm.
Akai MPC, stereo samples and great at sequencing polyphonic tracks on outboard gear.
I’ll have to experiment again to see if there’s a difference. But like I said, it did work about half of the time, seemingly randomly. Not sure if that’s connected to midi sync since the midi cc notes where purposely put all over the 64-step sequence to try to trigger it correctly if it missed the first note, but I never got it to work reliably. I suppose I should try to enable/disable midi sync then to see if that makes a difference.
Oh really, that’s surprising. I’m about to buy an SP404mk2 but now I wonder if you think it’s a mistake.
I have an A4mk2 and I just need a sampler to go perform Daw-less. DT has too little space and the OT just seems to have many things I don’t need, so I’ve pretty much decided on an SP404mk2. My biggest concern is not being able to sync up the different sequencers with matching pattern changes (like I could with an elektron sampler, or maybe the SP can?) so I plan on sequencing MIDI from the A4 to trigger samples on the SP, that way I can compose patterns on both and change patterns on the A4.
But maybe triggering the right samples at the right time will be tricky or something?
It works for me. Pattern Change aswell as triggering Samples is working with Syntakt and Octatrack. I use Midi Mode B. Clock from Octatrack.
Me too. My other synth gear is in boxes is sold or in boxes. I find that syntakt, Octatrack and hs explorer does all i could want in the synth, drum machine, performance world. Anything else just clutters and introduces troubleshooting
Cool, great to know. So to be clear, you can compose pattens on all the elektron banks 1-16 on A-J and when you launch them you can automatically have specific patterns to launch on the SP404mk2?
I don’t mind if there’s less overall patterns available on the SP or whatever, just hoping you can compose patterns on both without having to touch the SP.
Yes, with latest Firmware it works. I usually work in Midi Mode B and just sequence from Octatrack. But I tested also changing pattern and it worked.
Further testing with Syntakt as Master:
A-E Bank and pattern change worked. (PC: set to Channel 1 on Syntakt and Roland Midi Ch 1-2)
If you want to change Bank F-J in SP (PC: set to Channel 2 on Syntakt and Roland Midi Ch 1-2)