Well… it is spooky but true, even though it appears that the RROD only occurred to modded consoles, so honest people should not experience problems that big, so you can take a deep breath of air now. Also, remember to count to three and do that pretty often, because you’ll be put under a lot of stress by the new Xbox experience.
There are voices claiming that the slow downs and errors are caused by the huge amounts of traffic from the users accessing Xbox Live, so it could just be settled by itself in a couple of days’ time. Also, the little errors and bugs that generally occur in the Marketplace (wrong dates and other glitches) will probably be fixed by Microsoft ASAP. It’s been a huge update this New Xbox Experience and it is, unfortunately, natural to have bugs. But they will surely be solved, even though there was no official statement from Microsoft on the matter.
Update: I just saw that Major Nelson posted an update on this: “As you can imagine, it’s been an incredible day so far for the New Xbox Experience. It’s great to see so much enthusiasm…it sounds like you are having fun exploring NXE. With an update of this magnitude, reaching more than 14 million people around the globe, we are aware some of you may be experiencing a few hiccups along the way. The LIVE team is closely monitoring the LIVE service and Xbox.com and are aware of a few issues including what’s happening with Marketplace. The team is actively working on the issues, so thanks for bearing with us,” he wrote.