Franz 5

have been using it since the first version

No real cons, but the migration was a bit disappointing. All my logins were gone and I had to re-authenticate with each service, which with 2FA on is quite a hassle. So if Franz 5 Final could keep the previous auth tokens/cookies, it would make the upgrade smoother.

Another specialized browser

great service overall

Though Franz has been great, Station can still be considered as one of the strongest competitors, but I still think Franz is striking a better balance: what you need is all at your hand and what you may not or don't is just not in sight. Station indeed provides more options (such as keeping multiple Slack accounts online simultaneously) but personally I think they still need to polish the multi-account settings and controls.

Anyway, Franz has been doing a great job being a relatively light-weighted IM integration tool. WeChat being available alongside other IM services is highly appreciated :D Also, liked the cute loading sentences such as "twisting my mustache" and "playing the trumpet" etc.

Need help, I used the app for 1 month and had no problems. But after reinstalling the OS (High Sierra) and the app, I cannot add multiple accounts(channels).

You won't be able to use browser extensions on these web apps in Franz

Having used Franz for over a year I can definitely confirm that its a great all in one solution for running your messaging accounts. Its decent with regards to resource requirements but it does need an odd restart when it gets stuck. The only downside is the lack of updates. Overall, its well worth a look.