I have an assortment of acoustic guitars that I play through the S1. The one that gets played everyday is a Recording King Dirty Thirties 000 with an LR Baggs Element active pickup. It tunes and plays good, and sounds good with the S1 guitar preset, and just a touch of reverb. It and the S1 are always present and ready when I have an uncluttered moment to play and sing.
Others include some Martins, CEO7, SPOM-16, D-18GE, a Blueridge, BR163, a Taylor GS mini, and a Waterloo WL 14 XTR. All of these have LR Baggs pickups, either the iBeam or Element except the Waterloo which has a Baggs Lyric.
I use the preset for all guitars and EQ is generally near the midway settings. For me the S1 is primarily a practice amp/PA.
Curiosity got the best of me and I have recently purchased an EV ND 96 mic and have been using it for vocals. It is not drastically different from the EV ND767 that I was using before. The 96, which to my ear, lacks a little warmth when compared to the 767, might not survive use outside of practice, though it will be in the gig bag. The ND 96 has amazing vocal clarity and I imagine, in it's suggested use for loud stages in a band setting, it would cut through like no other. It is a great companion to the S1 if you value clarity.
In my playing career I have never used a designated guitar amp for acoustic guitar. Early on I sang through a guitar amp and my acoustic guitar was held in a manner that it was picked up by the vocal mic. Later when Small PA equipment became available to budding artists I miced the guitar through the PA. It wasn't till the mid 80's that pickups became "acoustic" enough that those of us who used mics would consider switching. It's interesting that with the S1, it is like going back to my beginnings, singing and playing my instrument through a single small amp, only now it works, much, much, better.