Accurately calibrated and with a good blade installed, any of the saws you mentioned will make a fine chessboard.
I am concerned about my digits because I work on computers, play musical instruments, and I need help remembering the number that comes after "nine."
I had a Bosch REAXX jobsite saw, which has a safety mechanism like a SawStop. (SawStop sued them over patents and they are no longer available in the US.) I replaced it with a SawStop PCS-175 cabinet saw.
The drawbacks of a jobsite saw are:
* Short lead-in distance from the front of the saw to the blade.
* Aluminum top is not as smooth, and it scratches and dents easily.
* Typically, fences are not as good as the ones that come on larger saws.
The new SawStop Jobsite Pro saw has a 2 inch longer lead-in distance, an improved T-track style fence, and better dust collection, along with other minor changes. Those differences (especially the lead-in distance) make it worth the higher cost over the old SawStop jobsite saw. They would have to discount the old saw a lot more before I might consider it over the new one. A LOT more.
I have not used the Ridgid 4512, but it gives a lot of saw features and capability for the money. Ask others about the fence to see if they like it. I imagine that it cuts "better" than any jobsite saw, just because of its size, the nice beautiful flat cast iron top, and more. By "better", I mean less effort to set up and line up an accurate cut than a jobsite saw, with more consistent results. Everything would be smoother and easier, including the cut itself.
I would not consider a table saw without a safety mechanism. The huge loss caused by one slip or mistake in terms of pain, grief, and finances is worth the cost of the "insurance" penalty that you must pay up front to buy a SawStop, in my opinion. I know enough really good woodworkers who are missing pieces of themselves, not removed by elective surgery. I am not arrogant enough to think that I will
never make a mistake over decades of woodworking. That's me.
Others argue that you must follow good safety practices regardless of which saw you use, and that is the path to avoid injury. They are right. I acknowledge and respect their points, but feel that we are all human, and mistakes happen. I respectfully disagree on the path to achieve adequate safety, and we go back and forth here often.
I want you to know that not everyone agrees with my opinion about table saw safety mechanisms.
Table saw safety mechanisms won't protect you against kickback, either. You can be seriously injured by a kickback from a SawStop saw just like any other table saw.
I replaced the Bosch REAXX jobsite saw with a SawStop PCS-175 cabinet saw. Considerations included storage space and mobility. It turns out that the SawStop cabinet saw has a smaller footprint for storage than their contractor saw. The contractor saw has a motor hanging off the back, so it stands further from the wall when stored.
If you buy a SawStop cast iron saw, get the 36 inch T-glide fence, not the 30 inch fence. If you get the cabinet saw, buy the Industrial Mobile Base for mobility. It is far superior to their simple mobile base and it is so worth the high extra cost.
If you are on a tight budget, I understand the temptations of buying the Ridgid 4512 over a SawStop Jobsite Pro saw. Because of my feelings about safety, I would buy the SawStop anyway, but most people would recommend the Ridgid, and they would be equally right. One consideration might be whether you have children or others who might use the saw someday. It is a personal decision.
If you have the money, a SawStop cast iron saw with a T-glide fence is a joy to use. But then you face the same decision - there are many excellent contractor and cabinet table saws from many manufacturers, for less money than their SawStop equivalents. Also consider "oldies but goodies" - the old cast iron saws of the past are practically indestructible and cut well, but lack many safety features.
Good luck!