It does have that. You just pick them with drop down or keyswitch. That said, I'd look at Elements instead. Not so much because of the additional vowels, but because it sounds a lot better to me. Now, maybe Micro can be made to sound good with proper programming, but Elements sounds great just as is.
 
...and I don't know about you but to me that sounded like a challenge saying "Please play with your toys and make a demo!" Oh ok twist my arm :).
 
This is a simple example with the "ahh" sound from Micro and Elements. Since old videogame music is what I like playing with, that is what it is (Descent if you were wondering). Also it is a useful test since this is not composed or tweaked at all for the libraries, this is just an ahh choir line fed in to it with no tweaking, other than balancing the volume.
 
Here is Elements
Here is Micro
 
Same MIDI data, same everything except volume level (micro plays louder than elements). I just unmuted one and muted the other inside Kontakt.
 
Micro isn't bad given the price, I don't know of anything else in that price range at all, but Elements is just far better to my ears. It also has other features like more vowels, a sort of simple phrase builder (where you specify a patter of vowels to cycle through) and so on.

Hey Sycraft, thanks so much for the info & demos.
Much appreciated. I'll check out Elements as well.

Gotta throw in a +ya for Soundiron. I've got the Mars and Venus package. They are stellar.

Realivox "The Ladies" is a nice set of female solo singers for Kontakt: http://realitone.com/realivox
 

jimusic
 
So does it provide the basic Oohs & Ahs - both male & female for $20?
 
That's all I really need for some simple pop songs backings.

For basic oohs and aaahs the choir in the Kontakt factory library is not too bad, but Olympus elements is a lot better for these vowel type pads, I use them more than the phrases.
 
Of course what you want to do with the sounds is important, most of these libraries tend towards the epic classical choir. "The Ladies" as mentioned by Tonecarver is more pop orientated than most.
 
The track in my signature uses a couple of the choirs in M-Tron pro. I tried replacing them with some more realistic choirs but I thought the 'tron choirs were best in this context.

Thanks guys. I had no idea there were so many different libraries like this out there. Some of those are are little dark sounding, at least my demo listens seemed to point to that.  Some of the higher caliber libraries that Glyn mentioned. I'm sure that they could fit into almost anything given the right programming though. 
 
" The Ladies" was one I checked out recently and was pretty amazed at the realism and up close feel I got with it. Like you say, would be wonderful for pop music.
 
Olympus looks like a home run...I plan to look into that one more. Their pricing structure is very fair and the quality of the samples is first rate. Thanks Steve for the heads up on that one.
 
I don't use vox samples in a big way, more like salt and pepper. Here is an example of how I usually use a vox sample.
 
 https://soundcloud.com/starise/days-of-splendor
 
You almost can't hear it. In this case I used the mellotron I bought from UVI awhile back. To me it sounded better than the staple ahhs I had in Kontakt....not that they are necessarily bad but they are starting to sound too vanilla to me. Apparently someone else thought so too and made some other libraries. Soundiron is very different but I like the way it sounds.

Ever interested in ethnic/eastern vocal libraries, this one is fresh and diverse.
Rast Sound "Mideast Vocals"
--rastsound.com/downloads/mideast-vocals/
It is for KONTAKT | WAV.
Lots inside,
* 6 Solo Playable Multisample Vocal Instruments (KONTAKT)
* 6 Long – Short Sample & Loop Players (KONTAKT)
* 37 Long Improvisations
* 38 Short Improvisations
* 32 Natural Loops
* 33 Processed Loops 
Demo Video,
https://www.youtube.com/watch?v=apCOwNmVcP8

This isn't a traditional western sounding choir, but it's one of my favorite vocal libraries. It's a Slavic Women's Choir from Impact Soundworks called Vocalisa. It sounds incredible and is a blast to play and write with. 
http://impactsoundworks.com/products/vocal/vocalisa-slavic-womens-choir/

I make heavy use of it in my track "The Oath" if you want to hear it in action from a regular user like me (not a demo from the company). 
https://soundcloud.com/ch..opher-porter-7/the-oath

Vocals are really hard to do well. Especially solo voices. Things like Realivox Blue do alright on sustained and drawn out parts, but the quick changing articulations sound robotic to me.

That is true because human voice is so diverse and reflects quickly even if there is a little non organic movement.
And this is why we produce not just solo instruments but improvisation-phrase instruments as well.
When you blend those, it becomes more natural-organic.
At least this is where we ended up in Mideast Vocals library for KONTAKT.