Pretty much per what ninwa said, though I haven't done quite a few of those units. Contract, Tort and Crim are basically on a par, although Crim is actually arguably the easiest, despite no longer being done in 1st year (I found it a bit more intuitive). Property A isn't as bad as Property B which has some conceptual difficulties. Consti...opinions seem to vary a bit. While it is not perhaps as conceptually difficult as some of Property B, I actually found it to be less interesting - rather dull in fact. There are a few interesting discussions, and Kirby usually has something to say that's worth reading (often in dissent), but the cases are sometimes long and boring. Pretty much every decision is from the HC and hence has a bunch of long judgments that often differ in minor ways and then have to be reconciled. Haven't done Admin but it seems to have a reputation of being a little harder than Consti.
Equity pretty much follows on from where Property B left off w/r/t conceptual difficulty...except it's closed book, so it's even worse. Have not done Trusts, Corps or Evidence yet but they all seem to have a reputation for being hard.