I used to be a regular visitor to Key West, but haven't returned since COVID-19 when I'd already decided it was time to stop going.
Island House is the last gay male resort on Fleming Street after the Equator Resort closed. Alexander's Guest House, as nice a property as it is, was also much more mixed LGBTQ/straight on my last visits.
Personally, I prefer Palm Springs which is great if you like mid-century architecture. There are certainly more upscale resorts in PS than Island House. I've had great stays at the Descanso and Santiago resorts, which along with Twin Palms, are part of the same group.