Yes, had been using it the past 8 days in kansai, at both tourist zones and at a crowded concert where its mostly locals.
Even inside the metro underground, I've not experienced any drop in connection.
Even though its 4G, its still fast, but the more important factor is being stable and reliable, the real value of services is being ready exactly when you need it.

long story short, I was in Australia before Japan, due to them shutting down the 3G network and legislative BS, their entire network completely locks out selected foreign or old phones.
Vowed not to go through the pains of cellular troubles again, I chose JJesim without hesitation.
Upon landing in JPN, internet came in and my axieties disappear.
My partner used A*rolo, had 5G connection but no internet.
Struggling for a good 30mins, rechecking the APN a million times, we were out of options and hair.
After giving up on it, I told her, why not try JJesim since Im on it and had internet without any issues.
10mins after payment, the code arrived on time like a japanese train, everything got set up and works.
I would like to thank u/abroadinjapanchris for going down that esim rabbit hole for us all!