Rasure
Does anyone happen to know the midi clock PPQN of S1? did a google search but couldn't really find anything.

http://answers.presonus.com/6747/shortest-midi-quantization-in-studio-one
https://forums.presonus.com/viewtopic.php?p=110476&sid=d896e32e0512a325035712e221e1ddd0
 

Looked at plenty on youtube last night and seems to do everything I need it for and a bit more.

I have started to use S1 2 months ago after struggling with sonar crashing. S1 has real time quantize feature that is very nice. Basically means you let the midi play along and play with the quatize strength still you hear what you are looking for. That is gold.

Studio one currently has a bug where midi notes are occasionally missed - 
See Presonus Answers - 
21036/some-notes-are-not-being-triggered-after-update-to-3-5-2-44603?show=21036#q21036
 
There are ways round it - using the previous version, or starting the song pointer at bar 2 seems to do the trick, and I'm sure Presonus will get it fixed at some point.
 

It only occurs when you have a looped section once it starts to play over again. And only occurs if you start playback from 0 as far as I know. So it's easy to avoid. They said they have fixed it an update is on its way.

This doesn't exactly answer the question, but Cubase and Cakewalk were the big names in computer midi sequencing when I was cutting my teeth (I was still using C-lab Notator on an Atari ST). They added audio later. So their heritage was in midi.

Tonight, I spent an hour trying to figure out how to set up a multitimbral instance of Kontakt, and I thought at one point I was going to have an aneurism. 

Setting up multitimbral instance is actually very easy in S1. You just have to click some check boxes in the mixer and it will create all the output channels you tick. You can also untick any time later to remove any channel. 

Get Notion, complete integration with Presonus.

Thedoccal
I have found nothing in the midi department so far that Sonar did that S1 can't do.
The problem is layout and execution of editing, routing, etc.  A different mind created S1 and it took me some video watching to see where everything was laid out.

S1 doesn't have Instrument Definition files so you can talk from within the application to external MIDI hardware like workstations and drum machines and pick/audition patches on the fly from the track, etc.  Cubase has this, due to its roots also being in the heyday of MIDI.  I use S1 as well as Sonar - S1 when my project is mostly audio.  An S1 user did write a usable plugin for instrument definitions a couple of years ago but I seem to have lost it now.

Well, for me the absence of ARA is the major, probably eliminating, negative about Cubase. I use Melodyne Editor often, and it's frustrating when it doesn't integrate smoothly.
 
***So, since S1 does have full integration with Melodyne, I'm wondering if anybody would know about S1 and whether it offers these more trivial (yet still coveted by me) features:
 
1) Varispeed (the "chipmunk effect" originally achieved by recording with the tape running slower and then playing back at normal speed) ?
 
2) Negative measure numbering (The ability to have measure one in the DAW line up with measure one in the written score; if there's material played in the measure before the downbeat of measure one, it's displayed as occurring in measure negative 1, and not as if it is played in measure (positive) 1.) ?
 
3) Custom track colour strips (I think the answer to this one is yes, but from quick peeks at Studio One this morning, the overall "look" of Studio One does seem a bit chaotic.) ?
 
4) Are the menus intuitive?
 
I know this question is impossible to answer objectively, but maybe someone might have an opinion on the following scenario: Let's say a musician inexperienced with recording on any DAW has the chance to use either Sonar Platinum or Studio One Pro for an evening.
 
 
He or she hopes to record (alone) a fairly simple short song including, say, acoustic guitar, bass, piano, a couple of voices and a Kontakt synth patch, maybe just add a little reverb, then mix and export the resulting song.
 
 
Which DAW would likely take him/her less time to work out how to achieve this, Sonar Platinum or Studio One Pro?*** 
 
I can use Sonar pretty well (ok, I admit it, not really ) but I'm wondering whether Studio One may be relatively more or less complicated (difficult to "get going" with) overall.
 
Thanks for wading through this!
LJ