I must say that about the biggest mistake I’ve made running this site was the decision to upgrade from Movable Type 3.x to MT4. If you’re running MT 3.x and things are okay, I would strongly recommend against MT4.
I can’t say how much of my trouble is truly MT’s fault and how much is JaguarPC’s fault. MT4 (usually) ran okay at first. Only a few hiccups. Initially the biggest downside was that my antispam plugin wasn’t MT4 compatible, but beyond that I’d hit a few errors that I hadn’t seen before and that was about it. But it got progressively worse and in one day in May it all went to Hades.
Today I hit multiple errors every time I try to publish something. If you try to post comments, you’re also probably hitting errors. If you try to open a page on MO, you’re generating errors. The process I have to go through just to get a post online is quite a joy. And if I want it to show up on the front page there’s another process I have to go through.
An older MT3 installation on the same server runs just fine.
Stick with MT3.
I suspect that my host made some changes to something that don’t play well with MT4. Fortunately, everyone tells me that everything isn’t their fault.
Unfortunately, I’m swamped right now with some other (non-blog) projects and the error-ridden MO is going to have to limp on for the time being.