What are the pros and cons of running a RPG session using Tabletop Simulator?
I have run some sessions of Dungeon World on there already, as well as a single session of Edge of the Empire - And it works like a charm.
The following is a list of pros and cons that I experienced first hand (playing RPGs, Dungeon Crawlers, Magic the Gathering and many other things on TTS, I bought it when it just came out, a long time ago) - There is much more to say for and against using the program for RPGs, but having a really long list with small nitpicks and praises will not be of use to you, so I will focus on the most relevant things.
- A fully 3d environment that almost feels like sitting at a real table
- Dice rolling is easy and has the feel of rolling actual dice to it
- You have access to a ton of useful tools: Endless Bags (e.g. useful for the dice in Edge of the Empire), Note Cards, a tablet to look up stuff on the internet, a separate notebook for each player and many more
- The Ability to import custom models, dice and Tokens
- You can paint (e.g. for making plans)
- Many people already made Mods for custom models and even custom RPG tables (Dungeon World, DnD, Pathfinder, the Dark Eye, even games like Maid RPG already have a functioning mod that provides you with everything you need. There are too many to look at all of them, though)
- Custom models allow easy building of Dungeons and other battle maps and some people have added many custom figurines to the Steam Workshop
- Scripting! While I did not make much use of this feature myself, there are existing Mods for e.g. randomly generating a dungeon layout and with a bit of a time investment, many things are possible.
- New features are still added regularly
- It is not free (like e.g. Roll20 is. And while Roll20 is not perfect if you don't pay, it works absolutely fine. If you don't pay for TTS, you're out of luck. And all you players need to pay.) The simulator is often included in sales, though.
- Character sheets are a bit of a problem: If you want to have it ingame (e.g. on the table), it takes up precious space and can not easily be moved because it is probably a simple object with text on it. Alternatively, you have to use stuff like note cards for the whole character (which might work for games like Fate, but playing e.g. DnD will result in a ton of note cards cluttering the screen)
- Custom content is not that easy to import (Models and Dice at least might require knowledge of Blender or something similar), you might have to rely on other people's mods
- Huge or detailed maps might be taxing for lower end computers or people with slow internet, resulting in desyncs or dropouts
- Players have to download all custom models and maps, resulting in additional wait time depending on the speed of their internet (and maybe wasting peoples hard drive space. Believe me, I had to regularly delete old stuff because I had multiple gb on custom models on my hard drive)
If you already own the Tabletop Simulator, I would advise you to just try it out for yourself. You will have to decide for yourself if the additional complexity is worth it for you and your players. (For me, personally, it was not and I returned to Roll20)
Be aware though (if you are the gm), that if you e.g. use pre-built maps (from mods) for your game, you might be setting player expectations that result in a lot of work for you. Keep that in mind.