Ones a pro bit of training software as you say used by most IR training schools the RAF etc.
And the other one is a mass market game with a dodgy flight simulation engine.
One is designed to lead you through instrument flying in a logical manner to build situational awarness with realistic instrument responses and lesson plans
And the other one lets you loose with no plan and allows you to develope bad habits.
One costs 80 quid.
The other one costs 20 quid which for flight training is proberly more than its worth. Added in the hardware required to get it to function in any sort of meaning full way. So Joystick needs to be added to the cost. And actually the older 32 bit versions are better for instrument training if you can get them to work on your operating system. You should be able to get that for a fiver which is realistically is its worth.
In the grand scope of keeping costs down RANT will save you far in excess of its cost so is good economics.
MSFX for a quick wazz round a procedure once you know what you are doing before you do it for the first time it is good enough. Actually learning about instrument flying it is useless and developes bad habits.