In fact, it's arguably a case of deja vu. More than a decade ago Apple had a similar offering called iDisk. It went through several iterations before Apple finally killed it in 2012. However, one important difference is that it was restricted to Mac OS X, whereas iCloud is cross-platform: OS X, Windows, iOS (highly unlikely it will ever appear on Android, though). It is priced competitively, with the first 5GB free and with paid plans starting at 20GB for 99c a month (possibly 79p in the UK).
Competition continues to heat up in the consumer cloud business. In recent months, both Google and Microsoft have improved their services and lowered prices. iCloud Drive will prove a powerful competitor, with special appeal to the Apple faithful. The biggest potential loser is Dropbox - actually considered the best of the bunch by many people - which offers the least free space of all and the most costly paid plans.