Other than the old MobileMe services like contacts, calendars, and mail, I don't believe the two are really the same. The main difference are the type of service (storage or streaming) and its automation.
iTunes in the Cloud will automatically push new purchases to your other devices and you can re-download them on other devices (max 10) multiple times. iTunes Match, while $25 a year, matches or uploads non-iTunes purchased songs and makes them available to your other devices. This isn't a streaming option though like Google Music Beta or Amazon Cloud Player. Definitely no subscription service like Zune Pass. It's simply just pushing new songs to your other devices.
Photo Stream isn't a photo storage locker like SkyDrive. SkyDrive is kind of a competitor to other photo lockers like flickr or Facebook--they're meant for sharing. Photo Stream is only automating the process of pushing photos you import/capture on one device and pushing them to all the others. So if you take several photos at a camping trip on your phone, they're automatically pushed across to your Mac/PC, iPad, etc. No compression or resolution downscaling.
This last one I think is the most useful part of iCloud. Developers can use iCloud storage APIs in their apps so that game saves, documents, or key values are never lost. New app downloads are automatically pushed to other devices (download on iTunes initially, pushed seconds later to your iPhone and iPad). Backups for music, apps, books, photos, device settings, app data, texts, and so on are all done over the air daily.