It seems that every reloading source has a different set of max loads per caliber. GRT has loads for powders in cartridges not listed anywhere else.
So how accurate and safe have you found these to be?

My tests on known loads has been positive. Predicted was real close to actual. I would have no problem working off a 5-10 step ladder derived from such.

I've found it's close provided you go through the steps of measuring case volume and using your numbers as opposed to the defaults. This also hold true for adding your numbers for case length, OAL, bullet length, etc.

Would the GRT have data on the 9.3x57mm Mauser?

Yes he does. I checked just Hawk bullets (.365"). 200 grain to 320 grain. Lots of others though. I had a bit of trouble getting it to work but with the help of a guy here it is doing well.
He has YouTube videos.

It it similar to Quickload or just loading data?

I never used Quickload. Sorry I can't comment.

It’s predictive software.

This is what Quickloads main screen looks like so you can compare it to GRT

GRT

The one think I look at using GRT is the powder burn calculations.

It is very similar to QuickLOAD but it actually has a few more bells and whistles. One thing GRT seems to lack is the ability to show a list of max loads for an entire range of powders like QL can. If there's a similar function in GRT I just haven't found it yet.

I don’t have QL but have seen the garbled up mess some post. But maybe this will help.

Here I have loaded in a 223 load of mine using Benchmark



Now if you go to that 4th button from the right and click on it this is what you get



These are all comparable powders by velocity only. Under conditions tab you can set the compatibility parameters.

Thanks Swifty. I'll play with that some and fork around with all the buttons a little more next time I wanna kill an hour or two.

Cool thing is that most of the powders all fall in the same general max charge as the original selection. If you click one of the powders it will pop up the profile tach like the one in the upper corner of results for comparison.