Anderton
And also be aware that audio-to-MIDI is an imprecise science at best. As with any kind of translation, the simpler the source material, the more successful the translation.

^^ This should be emphasised. I think it's more like a rule that people have very unrealistic expectations of audio-to-MIDI, no matter what software or DAW they're using.

Anderton
And also be aware that audio-to-MIDI is an imprecise science at best. As with any kind of translation, the simpler the source material, the more successful the translation.

I use Waves Tune and find it impressive and if anything overly accurate.
You also get a massive amount of pitch controller for every transition - depending on the settings you use.
 
But it's for single voice stuff, of course.
 
Using Ultrapitch to throw everything up an octave first, I use it on bass too. Good to get midi for notation and maybe unison synth bass. Transpose midi down an octave again then.

I'm seeing a different sort of issue and approach here: something that was done in Cubase--which I had a copy of about ten years ago--where audio peaks or "hitpoints" could be aligned with a midi file essentially by adjusting the TEMPO map.   I think there's something more or less equivalent in most midi software, these days.  
 
Not the same thing, btw, as the function in 8.5 which allows you to "tap" in the tempo in a way that actually modifies the tempo map from beat to beat.   (Useful, but not pinpoint accurate.)  The old "hitpoint" in Cubase approach allowed a dead-on accurate beat by beat manual adjustment of a midi tempo track to fit an audio track.
 
Probably old ground, here, but does Cakewalk now have an equivalent?  (I think the modern equivalent in Cubase is called "Warptool" or "Audio Warp" or something along those lines.)
 
 
 

You can match tempo to just about anything if that's what you want to do.  Either use audiosnap to quantise the audio to the existing tempo, or keep the audio fixed and match the tempo to the audio.  Your choice.

I've tried audiosnap in 8.5.   I couldn't get it to do FINE adjustments in midi tempo to make a midi file exactly and perfectly correspond to every beat, and subbeat (audio peak) of pre-existing audio file.  
 
I will research audiosnap one more time though.  May be I'm missing something.  i think the problem is that audiosnap isn't designed to do PRECISION MANUAL matching of every audio file "beat" to its corresponding "beat" or "note" in a midi file.  

Audio to MIDI conversion works for drum replacement. 
If what your after is taking say a audio track of a piano or acoustic guitar and converting it to midi, good luck. It's just not going to happen in a hassle free way. 
Because we can edit audio like midi now with tools like Melodyne there is not much call for complicated conversions. 

I'm not thinking audio to midi, the whole thing.   No.  Just something that will allow me to make very precise tempo adjustments to the midi file so that it "maps" exactly the audio file.  I'm having a feeling that only cubase sx, which is ANCIENT, does it.   Here's exactly what I'm referring to:
 
https://www.youtube.com/watch?v=QOzRDwP6vZE
 
But I guess there might be an equivalent in the latest Sonar?   Maybe?   Maybe not!

johnlewisgrant 
But I guess there might be an equivalent in the latest Sonar?   Maybe?   Maybe not!

SONAR's emphasis has typically been on conforming a MIDI sequence to the tempo, not conforming the tempo to a MIDI sequence. However, AudioSnap has some tools that may be helpful: Extract MIDI Timing Information from Audio and Snapping MIDI Edits to Audio Beats. Copy as MIDI might also be helpful.