As Lrsky pointed out, theres been some changes over the last years with flat speakers. No doubt theyve improved.
From my perspective, they are indeed different. Not better nor worse than any other sort. They seem to have a non directionality about them. Though often IF matched well with amp (s) they image exceptionally well. Better than many box speakers Ive heard.
They also consume some room geography. They need space to be set up well. Many need substantial power output. Bass is an issue moving from cone types into panels for many.
If youve ever heard dipole speakers or IOW omni directional speakers, you have gotten a tip on the sound of electrostats. Very unfatiguing and relaxing sounding transducers whose sound surrounds your ears rather than beats on them.
The only ones Ive liked were actually hybrids. Powered sub units down below, and panels up top. The Martin Logan Odysseys sounded OK to me and The top Magnapan sounded ok to me years earlier too. But the sweet spot is tight, the bass wont ever thunder or impact the way it should, they need space for proper setup.
But theyll never hurt your ears, image like no bodys business and esthetically will be a real conversation piece . OOOh and the bigger the better in terms of lower end reproduction.