Definitely, personally.
There are just many mobilesubstrate addons and tweaks that I have found either extremeley useful or just pretty cool
Things like Gridlock, Icon Renamer, SBSettings (or BBSettings now maybe), InfiniDock, Switchboard. Things which I unfortunately can not change on the stock version of the iOS.
And then there is WinterBoard. A lot of people hate, or don't even bother with it but personally I like swapping themes from time to time and changing things around. Sure, it's not for everyone, but personally I love it
iOS 5 has gone a short distance in replacing things I use from Cydia (Mark read & OpenTabBackground is all I think of for me, personally), although obviously the lockscreen additions, notification changes are awesome extras but there will always be something extra that Cydia will offer me personally