Well I have had much experience I can share.
I use a modern LCD HDTV that's multi-region and multi power ( 110, 220 ) that you can get from 220 Electronics.
Its obviosly does 50/60hz and everything in between . PAL, SECAM, NTSC 4.3 and NTSC 3.58. It sees everything that I throw at it from composite from the ST. My TV also has a " autotune " feature that scans for the signal.
You can get composite out of the ST's if they have the RF modulator, and it will upscale to HDMI. I use a converter made by Cable Matters.
You can get Composite out of an ST WITHOUT a modulator by putting in a few components where the missing modulator is. Pic #1 unpopulated, Pic#2 populated. The Mod is by Paranoid Little Man.
There are cheap monitor to composite cables on ebay, and Hercules Workshop may have some as well.
My TV/Upscaler combination has worked for Amiga's as well.
I hope this helps.