Dr Gannon made a pitch for TTS-1 for a free GM soft synth here.

I used TTS-1 for years and it's better than just ok.

I'm using the Roland SoundCanvas GM soft synth now. Think I paid $50 for it on sale. It's a little better than TTS-1 to my ears, even though both are based on SoundCanvas sounds.

Both are "assign it as default and forget it" if that's what you want to do.

DC Ron
BiaB Audiophile
Presonus Studio One
StudioCat DAW dual screen
Presonus Faderport 16
Too many guitars (is that a thing?)