When I started composing (early 2010s) Pro Tools was known to be crap when it came to MIDI.
The best DAW for MIDI composition/writing, etc at the time was Logic, but I didn't (and still don't) own a Mac.

Pro Tools has changed a lot since then. Can anyone vouch for it's midi composing capabilities nowadays (enough to justify the price tag)? Does it have expression map support, is it easy to automate anything inside a plugin, that kind of thing?

I am used to Studio One. So far my favorite DAW, but every once in a while it just causes many problems, always when I am in a time-critical project.

To me the 'integration' it shares with Sibelius makes it even more attractive.

 

nope. no way jose.

 

If MIDI is your primary goal then Cubase or Logic. They have been the MIDI mainstays since the 1980s, when logic was Notator, and Cubase matched it equally in MIDI. Studio One has ex Steinberg devs so it is based on Cubase MIDI but minus a few features. ProTools is not known for its MIDI friendliness, quite the opposite, unfriendly. If Sibelius integration is your goal, fine, otherwise I'd stick with Studio One, which in some ways is more friendly than all of them. Cubase and Logic keep all the Sibelius data, phrasings, dynamics, trills etc etc etc if you export MIDI from Sibelius and import MIDI anyway.

 

Same. I've been using Pro Tools since coming over from Studio Vision in the late 90s and have always just "dealt" with the MIDI implementation. It works. Not much more than that. But it works. I switched to Cubase a few years ago and love programming on it. But in my scene, 95% of the time I'll eventually have to convert the sessions to PT to work with others so I find myself gravitating back it more often than not.