I've tried a number of chat tools including a few on this list. I'm a big fan of Crisp. Their mobile apps and usability I think is one of the simplest and cleanest to use (in contrast to article). Also the free tier is super generous and I've been running it for free on multiple sites for years.
For me a mobile app was a must and Crisp has one of the best.
As a pre-product-market-fit startup, I was looking for the cheapest option, to basically figure out if people would message me at all or not. (They do!) I've started with Drift around half a year ago and everything was broken. (Maybe they fixed everything by now, can't tell.) Went over to Crisp and I'm super happy with it. For now I'm still on the free plan.
For me a mobile app was a must and Crisp has one of the best.