Reddit definitely has better features. It's not even a competition. The reason we're here is because of the Reddit administration and because of future potential. Eg, the apps are so new right now that Reddit's official app is better. But in a couple of months, that won't be the case anymore.
I do too, but this thread is about ways to filter or block content so I'm not really sure what that has to do with it?
I'd love a way to filter by keyword, which the Reddit Enhancement Suite and some of the 3rd party apps allowed. Maybe the upcoming Sync for Lemmy will port over its filters by domain, user, subreddit, flair, and keyword.
As for Reddit posts invading Lemmy, it seems like most of them are contained to c/reddit and c/RedditMigration, so blocking those two should fix most of OP's issue and that's easy enough to do without any extra tools.