It's when the price difference is vast like you describe that GTY can be worth it. Most of mine have been suite GTY and my opinion is there is no such thing as a bad suite.
For other categories you do have to assume you will have an assignment very far forward and probably on a lower deck.
Don't assume you will be able to change cabins (in the same category) after a GTY assignment. I have several times but once since the restart I was refused. I was assigned the first S2 Sky Suite at the bow. There were 30+ open suites so I requested on by the elevator. I was told if I wanted to change it would be at prevailing S2 rate. I argued that I had done several times before. Shoreside concierge held firm that's why the GTY is lower price, you get what you were assigned.
The story did have a happy ending as when my TA was back on Monday I asked him to change the cabin and it was done in 5 min.