Honestly, you will never know what fits you until you try them both. I started using drum machines on stage back in the 80’s when I bought a brand new Sequential Drumtracks. It was a great box that I really connected with. I loved being able to program the volume and tuning of each note. We covered a lot of Prince with that machine, along with Rocket by Herbie Handcock. A few years ago I bought an ARmk1 thinking it would be great, but I never connected with it. Bought a Digitakt and loved programming it and quickly paired it with my TR8S. At some point decided to try again and bought a ARmk2. No connection. I like my Syntakt, love playing around with the Model Samples and Cycles. Have my Digitakt 2 on pre-order. Not sure why I don’t connect with the AR, but if I had not tried it I would still be lusting for one. You are just going to have to jump in and try to really know which one is for you.
I will say, if you buy a used ARmk2 at a good price and don’t like it, you can always sell it.