User-friendly features, easy to onboard new users. I found it particularly helpful as I've got 3 kids so communicating via audio makes a big difference to my productivity (much faster, easy to use). Competitor solutions either have a short time limit (e.g. LinkedIn has a nice audio feature but it's 1 min max which is not practical in many cases) or accidentally break too often (e.g. WhatsApp voice messages accidentally cut out very frequently so you end up sending broken audio messages). The customer support team has also been extremely helpful any time I had any questions.

I love using Yac to replace meetings with voice messaging and screenshares.