The ML-1 is a large-diaphragm condenser mic. This topology* is used extensively in classic microphones and favored for many reasons. One reason both large and small diaphragm condensers are selected over other types of microphones (such as ribbons and dynamics) is their ability to capture extended top-end in a clear, bright manner. It is for this reason that reference and measurement microphones are often condensers. Ribbon mics and dynamic mics have a naturally softer sounding top end, and often (but not always) a more limited frequency response. This is normal for a ribbon or dynamic mic and often an advantage, but in a straight comparison a condenser mic will almost always be perceived as "brighter." Consider this when making comparisons between mics, and consider the topology of the mics you are most familiar with.
Similarly, the VMS-1 is a transformerless, solid-state mic preamp. This topology is selected when the flattest, widest bandwidth, widest dynamic range mic preamp is desired. A tube mic pre will, in most circumstances, have a less flat frequency response, limited in both bandwidth and dynamic range, and significantly higher in THD. Such a preamp may still sound amazing, as many tube preamps do, but if strictly flat and wide response is the goal than a transformerless solid-state preamp will be the best bet. The VMS-1 system was built to deliver the flattest, widest signal possible to the ADC**.
It's important to consider these factors when making comparisons. The ML-1 into the VMS-1 will and should sound brighter and flatter than a ribbon into a tube mic pre. This is key to the operating principle and necessary for the software to function. We must send the widest signal possible to allow for accurate modeling.
The ML1/VMS1 system is designed to complement the software and create compelling, lifelike recreations of specific analog hardware combinations.
*In electronic circuits, "topology" refers to the operating principle and component arrangement. Examples of different topologies are Tube vs. Solid State, Large Vs. Small Diaphragm, Ribbon vs. Dynamic vs. Condenser, etc.
**Analog to Digital Converter. The circuit that your analog audio signal goes through to become digitized and usable by your DAW. See the block diagram here.