On desktop, either the vanilla PWA for Lemmy, or alexandrite.app. I Really like alexandrite.
On the phone, I flip between Thunder, Summit, Sync, and Connect. Gotta keep a tab on how they develop, and I like them all, for different reasons.
Edit: my current preferred client on mobile is Thunder. Like you say, it feels like a modern way of browsing Lemmy, it’s really good.
Unlike twitter, if there are UI issues, people have a lot of options to try different clients, both mobile and web. I don’t use one only, I flip between a bunch of them, both on web and mobile. Sometimes the vanilla Lemmy experience is what you want, other times someone might have made a great ui for browsing one specific community that you subscribe to.
I’m also somewhere against the argument of it being difficult to pick a server, too difficult to know if it’s the right one for me, etc etc. In other parts of life, people make decisions on this all the time, day in day out, without batting an eyelid, and even on issues with a bigger impact on them, than which federated instans they sign up to a service on. Mobile phone subscriptions, which email provider you should use, what internet provider you should sign up with.
For some reason, social media seems to be one of these areas where we think it’s totally fine that monopolies exist, and options are not… an option. We need to resocialise the idea that it doesn’t hurt to make a conscious choice about where you lay your identity online, and what you sink your time and attention into.
There’s also a good Darknet Diaries episode from January about Bike Index and Bryan available: https://darknetdiaries.com/episode/153/