ClearCase is a pain inna ass...if 1) you don't have sufficient privileges to do your work (fairly common, until the admins loosen their anal sphincters about their "brand new toy"), 2) if the server is underpowered, or doesn't have enough resources allocated for it (corollary: They always underestimate), 3) The network is anything less that 10Base100, and 4) the admins are inexperienced, clueless, arrogant, or stupid (this is an inclusive 'or').
I believe I've described 95% or the environments in which ClearCase is deployed.
However, I've worked with it in one of the 3 documented cases where none of the above caveats are present...and it is a dream (compared to the other VC systems I've had to deal with.
Since you've just switched, the MTBS (Mean Time Before Shakedown) is about a month, so consider that things are not going to go smoothly for another 4 weeks. After that, things may actually start working.
And if they tell you they're going to implement UCM before they get everything working smoothly in base Clearcase, shoot the admin!!!
(And, no, I'm not a ClearCase admin, nor do I own stock in Rational...are you kidding?!?)