I have not heard both side-by-side. One model of Allaert that I head (cost something like $15,000) in a friend's system did not work well at all IN THAT SYSTEM. He uses the Boulder phonostage and Boulder linestage. He simply does not have enough gain, so he has noise issues and the system sounds a bit lacking in dynamics. In a dealer's system, using a custom-designed phonostage with the top-of-the-line Audionote step up transformer, the same Allaert sounded terrific -- very refined and composed, but not dull and lifeless. I've heard a cheaper model with the Audionote M-8 preamp, and that combination worked well too.
The Transfiguration Orpheus is a cartridge I like a lot. I've heard it in the systems of two friends, and I got to borrow one for about two weeks. I really did not try to optimize the loading in my system (big pain to do with my Viva Fono), but still, I got very good sound. Compared to my Lyra Titan, the Orpheus has a slightly elevated midrange that makes the music sound vibrant and exciting, and not as "cool" sounding as the Titan. It may have been slightly more shutdown on top and not as "fast" and detailed as the Titan, but, that too could be a loading issue. Both behaved similarly in terms of tracking ability (very good). If you are familiar with other Transfigurations, such as the Temper V, the difference is that the Orpheus sounds more dynamic and lively (I liked the old Temper Vs neutral tonal balance and composed sound, but thought it was too lifeless for my taste; the Orpheus is a BIG improvement).
I wouldn't overlook the Transfiguration Phoenix. At a much lower cost this is a lively and fun sounding cartridge. If you are looking for something that is very composed, and well balanced, and you are willing to give up a little on ultra detailed sound, the Ortofon PW is another interesting candidate.