I'm not sure how TMG handles alternate names behind the scenes but as a user, here's what the "married name" experience was like:
Every time I entered a marriage, it asked me if I wanted to create a married name for the bride. Clicking yes created a new tag (or "fact") called "Name-Marr." Each time I had a fact, there was a pull-down menu next to the person's name that allowed me to choose which name to use in the fact. (This was true for all name variations, not just Name-marr.) I didn't use the sentence structure to point to the name. It was selected via the pulldown menu. So, for example, if I had a woman as the grantor on land deed before marriage and as grantor on another land deed after marriage, I would have 2 land deed facts, both using the unmodified sentence template, but I would select different names from the pull-down. I would end up with two different sentences as output: "Jane Maidename sold X acres..." and "Jane Marriedname sold X acres." This function was also very handy for keeping track of alternate spellings. I could easily associate the spelling on the record with the fact.
I should point out that the "fact" screens work in a completely different way in TMG than in RM. In RM, the fact is created from the individual. The only way I can tell who the fact belongs to is by looking at that little window on top (sorry - don't know what it's called) or the title of the tag. [At least, that's the only way I've figured out so far in my 2 weeks in.] In TMG, the fact screen behaves more like the "share event" screen in RM: I could choose who to put in the fact and where they belonged. I had a slot to enter the ID # (or browse out to a people list) to enter the principle. Ditto for witnesses. I could change my mind about how to structure an event so that the individual who started as the principle could be moved to a witness role. I simply deleted their ID number from the entry box and moved them to the ID slot for witnesses. I could also add a new person to the database from that main fact screen, which was incredibly helpful for events with lots of people who may be new to the database (bondsmen on marriage licenses, adjacent land owners on deeds --- I can't tell you how many times I've later figured out these "strangers" were actually part of the family.)
While it's true there was great flexibility in TMG sentence models, I've assumed it's because of the greater flexibility on the data entry side. As an example, there is no restriction defining a fact as "individual" or "family." Rather, there are events and they have some combination of principles and witnesses, who may or may not be related. Two principles (like grantor and grantee on a land deed) could be unrelated. Like RM, there were pedigree and family views (neither as nice as in RM) but my main screen was the person view (similar to the timeline view but without the graph and no extra facts (like sibling or parent marriage facts where the person wasn't part of the event)). I added other windows (children & siblings) to show closely associated people on the single screen. Essentially, it was a hybrid of the family view and the timeline view but with spouses & siblings included. The reason I bring this up is that it underscores what I believe is the fundamental difference between the programs: RM views the world through a family lens (hence "individual" facts and "family" facts), while it seems to me that TMG views the world through a series of events and people interactions. The flexibility of the program reflects those views, in my opinion.
I view the programs as largely similar but the user experience feels very different to me. RM feels more like a family tree software, whereas TMG feels more like an information database. Things in RM are more defined and TMG allows the user more room to customize. With that flexibility, however, comes greater complexity, so I think RM is easier to use if you're just entering standard facts with typical sentences. That simplicity becomes complex, however, when you're trying to customize & keep running into the imposed boundaries.
Please don't take this as a knock against RM. I prefer the aesthetics of it, and there are many features that are superior to TMG. But I'm definitely having to rethink how I navigate through the program and design facts! And of course, I'm on a learning curve.