Well, the S1 is an “old” unit obviously, no longer in production as far as I know. That need not be a problem and if the price is really good. Obviously some of the more up to date features in Serato (like Flip for example) won’t be taking into account with the design/layout of the S1 as it simply wasn’t around. I don’t know how well Pioneer/Serato do support (firmware/drivers) for end-of-life gear.
Clearly you’ll be losing the performance pads, but that would be true for the MC6000mk2 as well (although there is at least a way to trigger samples on the latter), but that can be solved by getting a NEON or something similar.
Especially in light of your question about Serato remixing, I think performance pads in combination with Flip features are a great way to start.
My personal recommendation would be either the Pioneed DDJ-SX2 or the Denon MC6000mk2. Both are great controllers supporting Serato’s newest features and including full Serato versions. If portability and/or mic use is an issue, the MC6000mk2 takes the cake. It’s also by far the most sturdy unit controller land. Having owned and used the mk1 for years, I can safely day it’s a veritable, indestructible tank. It’s compact for travel, but not a lightweight.
Also, but this is important for me and many other mobile DJs (not sure if it is for you though), the MC6000mk2 features matrix inputs. There is a LOT of gear you can hook up and you can usually assign any input to at least two channels, giving incredible flexibility. Again, it’s a big plus for me, but might not be for you.
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