Having used MT 4 for a bit now, there are some things that I don't love about it. I often forget to set categories because it's more clicks than it used to be. And I have to remember to go into the Crosspost To settings to crosspost to LJ (though it's nice that I have the flexibility, it would be nice to set it to default to xposting). It's more clicks to post a new entry (though I changed my bookmark so it's fewer clicks again). Overall, though, it's a huge improvement in the interface, etc.