Yeah, I've used it a few times too and was able to get good results.   But the convenience and layout of Rematrix UI works to well for me to pass it up. 
 

http://forum.cakewalk.com/FindPost/3220191
 
Sadly I never got a response which is sad as I bought all their other products.
Oh well... No sale then.

I've been adding some IR's to Matrix Solo and now I can't add anymore. The "Place files here" is gone. Did I accidently delete it? How can I add some more?
 
Too bad about Overloud, I was thinking about upgrading to full, too.
Michael

Reflektor is good. I have to confess I tend to forget about it because it's inside Guitar Rig, which I never use.

You can move user patches into one of the other folders by changing the letter in the square brackets in the name column. Make sure to save a copy of your file before you edit it!
For example:

[U] BigRoomMono (1) 

If you change the U to a H it will show up in the Hall menu not the User menu. 

[H] Hall
[R] Room
[P] Plate
[E] Early
[S] Special
[U] User

Doesn't seem to matter if the impulse is in the usersIRs.rir or the IRLibraries\FACTORY.rir. 
Now if you could just make new menus...
 
I used SqliteBrowser to edit the 2 rir files. Don't change the hash, num_samples or waves columns.
You can probably re-order the list by changing the id_irwave column. Haven't actually tried but it seems to be the sort order.