Never used old LW much, but I'm a longtime SSC reader. I read the goals and strategy and hopes this project succeeds. My impressions so far:

-Everything's very minimalist; it seems very trendy and a little pretentious (though I suppose this is a matter of personal taste). A bit of color could help things like usernames to stand out. A bit of clutter at the top, in the form of a permanent header or sidebar (as opposed to the current, click-to-view menus) might help with site navigation, loading times (I don't do web design, but this seems like a thing), and making the whole place seem a little less self-serious.

-The site is slow. Slow to load, yes, but I experienced a lot of lag just writing a comment last night. (Maybe all my neighbors were watching HD Netflix last night though, as it's only minor lag right now. EDIT: Now the lag's back. I guess the site is only fast for me during low band-use hours.)

-I spent five minutes looking for a way to mark sequences as read, and then tried reading one essay at normal speed to see if I could then tell the difference between it and an unread essay. This is marked as "Done" on the feature roadmap, but I still have no idea how to use it.

-I really like the idea of cross-posting here from personal blogs. It's not obvious to me how to do this. Is that what a "Link post" is?

-I like the search feature; it's speedy, and I like how I don't have to leave the page to see results. It would nice to see more than three post and three comment results though. Also, when I click "LESSWRONG" at top left, it took me to the homepage but left the search view up. It would be nice if this link deactivated search; I was briefly left thinking the link hadn't worked at all.

-I don't want to see "Recommended Reading" every time I go to the homepage. I've read most of it. I think it's good to have on the homepage, but I'd rather it be further down or in a sidebar or something. Else, we could have a landing page with recommended reading and a recent activity page that people who just want to see what's new can bookmark.

Of those, only website speed and cross-posting is likely to affect whether or not I keep using the site. Mostly, it'll come down to adoption. I hope the project succeeds; it would be very nice to have a functioning central hub for rationalish stuff.