I have never actually owned ESLs but have had a number in my system and listened to many more, probably all the biggies (KLH, Beveridge, Acoustat, Quad, Soundlabs, Martin Logan, Sanders, etc. -- forgotten many of them, and of course the hybrid HQD system had ESLs in the midrange, sounded pretty durn good to me the few times I heard one). I have owned Magnepans for years (decades) and heard Apogee, Carver, and a few other planer dynamics or ribbon speakers. They all have pros and cons.
Disclaimer: I have not spent much time listening to newer models. Every time I post in a listening thread I get told how out of date I am. I have heard ML and Quad in the past few years but not Soundlabs nor Sanders. To me they are not revolutionary advancements over what I recall, with the possible exception of ML who seems to have resolved the panel/woofer matching that IMO was really bad about ten or so years ago. The newer models do not seem to have as glaring a transition from panel to woofer.
ESL's have that gorgeous midrange but full-range models often sound bloated in the lows to me, and the highs tend to be a bit harsh (many times because the amplifier does not like the low load impedance at the higher frequencies). They also tend to be pretty directional, which is a plus and a minus depending on how you think about it. Most ESLs are hybrids with a conventional woofer, and some use a separate tweeter (though few seem to do that now). Blending the panel to the woofer is always a challenge, and the image changes as you go down low (note crossovers are up in the 200 ~ 400 Hz range for a lot of hybrids). In the past ESL's had more limited dynamic range for playing loudly, though I think modern designs have mitigated that quite a bit. Even thirty years ago most ESLs would play more than loud enough for me, but anyone who's had them has probably heard the dreaded arc...
Magnepans and other planer-dynamic/ribbon speakers to me sound a little better over their full frequency range and the image is more stable. While IMO not quite matching the ESL's for midrange sound, they come awfully close, and with large bass panel area and line ribbon tweeters I prefer their low and very high end to most ESL's I have heard. To me Magnepan's offer a more balanced sound over their frequency range, a range as broad or broader than most panels.
The usual caveats about room and amplifiers apply; it takes a good amplifier and good room to hear any dipole at its best.
I would not say one is better, they are just different.
And I think any of them, like most other speakers ("full range" or not) benefit from a good sub or two.
All IMO - Don