My opinion is that the March 2013 contest was harder than the usual Codechef long contests. It seems that there were more HARD problems than in other such contests (I was expecting 1 or 2 HARD problems, and instead we got 3 HARD problems, with 2 tricky MEDIUM problems - ZENCALC and SUBTREE : although SUBTREE may also be considered borderline HARD, I guess). This made the contest more stressful than usual for me (because I wanted to solve all the problems) and also left me with less time than usual to focus on the CHALLENGE problem (which is one of the things I like best in these contests).
Anyway, on the other hand, I am also nicely impressed with the difficulty of the problems. It is not easy to come up with HARD problems which are tough to crack in a 10-day interval (many problems in other contests are HARD also because the length of the contest is shorter, but HARD problems in a 10-day contest need to be harder than hard problems in short contests).
Still, if I had to choose, I would prefer slightly easier contests in the months to come