I was a late acceptance beta tester. I've been using MSN since December or January (I cant remember exactly when).
There have been some improvements--adding bulk keywords, if you can call 100 at a time bulk, and they tweaked the approval algorithm to fix most of the mass keyword rejections, but it seems like things have gotten even worse since they opened up to everyone.
My experiences with support have not been good. I have called twice and both times the support person was not knowledgeable about the product. Both times they were very pleasant, but that doesn't go very far.
Email support (once I found it) has been spotty at best. I've gotten multiple conflicting answers to the same question. Lately I've just scaled back and have been waiting it out.
Reporting has always sucked and it continues to suck no matter how much we gripe about it. The interface is cumbersome and non-intuitive. There are basic features that are missing (how can you delete underperforming keywords when you can't see how the words have performed when you get to the delete page?) that are probably so far down the priority list that I have little hope they'll be fixed.
Here's the kicker--I have a few campaigns that performed very well in google that I have duplicated here. I have been getting an excellent return and I'd LOVE to add even more campaigns, but without decent reporting and a usable interface I can't risk the money or time. It's sad when I WANT to give them my money, and they won't give me a product worth paying for.
To say I was shocked when this product was released from beta (if you can call it that) is an understatement. I'm still baffled.