It can take 15 seconds for my iPad to connect to the store over wifi. Similar results on my Windows desktop and my Apple laptop.
A download will fail at least a third of the time. If I'm downloading more than one thing, or the download is large, say a movie, I almost always have to restart the download.
Television shows continually reset themselves as unwatched, or split themselves into two seasons.
Items that are downloaded to the computers or devices suddenly make themselves "unavailable" and have to be downloaded again.
I happen to have a router running dnsmasq, so I could use different upstream DNS servers depending upon the query (i.e. route CDN domain queries to my ISP and everything else to Google), but I found it not worth the trouble. TWC's DNS isn't that bad... I do override their search page for non-existant domains with NXDOMAIN however.
Also I have no problems with YouTube, Netflix, Hulu, Amazon instant video, etc.
EDIT: Before anybody suggests that I try different DNS servers, I have.
This year Apple has usually maxed out at 20-30 Mbyte/s instead of the 100+ Mbyte/s I get from some servers.
Move to KC — we also have great BBQ!
It's not a connection issue. On several occasions after running into this iMessage issue, I have emailed the picture full-res without problems.
That said, I don't think iMessage is terrible. I love it when it works as expected.
iMessage, on the other hand, has mandatory delivery confirmation (so you can at least know if a message is going to be problematic) and optional read receipts.