I'd go with Monarchy, mainly because they are still in business (not to mention they make quality relatively inexpensive gear). The Monarchy gear is also newer technology.
Take the Monarchy DIP 24/96, it's the best tested, among AudioAlchemy Pro32, Theta TLC. Outperform almost every model with similar feature. I used it for 5 years. Used a AudioAdvisor DTI, and then upgraded to AudioAlchemy DTI-Pro v2.7, then Pro32, at last I started using Monarchy DIP MK I, then Mark II, then now 24/96. The 24/96 sounds the best. Pro32 is also okay, but the component inside is not audio grade, and it sounds not as accurate and organized as DIP, the 24/96 had a major improvement over DIP MK I & II. I just upgraded to a Sony SCD-1 and I am STILL keeping the DIP 24/96 for future use.
I have DTI PRO 32 conected to MSB Link III !!!
I never expirience better imptuvement
in digital soud !!! For that price. It goes well with MSB Link III. With good, I mean real good digital cables betven will take your sound to completly diferent level. Great !!! So far DTI PRO 32 is stell in the game as one of the best !!!!
Compared my old AA DTI-Pro to a friend's DIP. DTI-Pro sounds sort of adds a golden shimmer to rock&roll cymbals. Massed strings also sound sweeter with the DTI-Pro. DIP (not the 24/96, never heard that one) sounds more accurate and true. The DTI-Pro was definitely adding something to the character of the sound (with an without the 20bit dither engaged) in addition to the jitter reduction. (This was with both an Adcom GDA-600 and MSB Link III DACs.) So it depends on what sort of sound you are looking for.
When I still had my Audio Alchemy stuff (DLC and OM-150) with my Eosone speakers, I liked the sweetness the DTI and GDA600 gave together. It smoothed out a bunch of my rock and heavy metal recordings.
I tried both the DIP and the DTI-Pro with my current EVS DAC, and neither did much for me anymore. So each system is different. If you want jitter reduction and a smoother sound, get the DTI-Pro. Else, if you just want jitter reduction, get a DIP or a maybe a better transport, or something.