I’ve had my 8S and MC-707 out this week to see if I can find a place for them in my all-new, all-now streamlined setup, and for the classic drum task I’d definitely choose the 8S - you can hear the results of ACB when you trigger certain sounds in fast succession, for example, which you’re not going to get on the 707. I also ran some A/B tests with the drum synths on the Force, which is what I’m using as the centrepiece, and flexible though the Force is, the 8S produced by far the best 808 kick, with a minimum of effort.
What I don’t like about the 8S is the limited hardware editing - it’d be significantly better if you could assign all three channel knobs to any parameter, like you can on the 707. As it stands. if you want to add a filter knob on a channel, that’s your hardware control used up, aside from the fixed pitch and delay controls - and this also applies to parameter locks. Coming from something like the Rytm, that’s a huge step down - as is the single LFO per kit. FX slots per sound is great, but again if you want to live-tweak or record any parameters, your options are limited
So I’d say the 8S has the basics really well covered - it sounds great, has a ton of sounds onboard as well as sample playback, and the classic sequencing is there, but it suffers when it comes to extras. In terms of adding some variation, subtle or otherwise - bringing a pattern to life - the Digitakt with a good sample set blows it out of the water. The exception would be if you’re into performing live, where 8S featues like the faders and being able to reset a sound or kit would be more valuable than being able to micromanage parameters.
For my part, I find it hard to deal with sequencers that aren’t up to Elektron standards - it’s never long before I wish I could do X or Y, even if it’s something as simple as temporarily lowering cutoff and raising a delay send - a couple of seconds’ work on the Digitakt, virtually impossible on the 8S.
The 707 is a little better on the control / sequencing front because you can assign all three knobs freely (plus one virtual extra). You also have the opton of using a synthesized kick, for example, alongside samples. The I/O options make it a nice little hub, and it’s generally a great jack-of-all-trades device. But for all the extra features it brings over the Digitakt, once again, it’s that Elektron sequencer that makes the most difference. With the 8S and 707, you will occasionally feel like you’re pedalling uphll. On the Digitakt, it’s downhill all the way (in the best sense).
As I mentioned, I’m using the Force as my main device, mainly for its disk streaming and arranger features, but even there I’m regularly frustrated when my Elektron muscle memory doesn’t pay off.
tl;dr: Digitakt + samples beats ACB + limited sequencing.