I just finished the OCP developer certification, taking my last exam yesterday. exam 101 (PL/SQL) was, I think, the easiest, as it covered the smallest territory (9 categories) compared with, for example, Intro with 23 categories or Forms I with 27 categories. By all means, get the STS software and practice, practice, practice. The study guides were OK, I own 3 different books, but the Developer software itself has a good help library and answers most questions giving good examples - in some cases clearer than the study books themselves.

BTW, you should be pursuing the 6i track, as Track 1 is due to expire in July and Track 2 maybe 6 months after that. Furthermore, the new track 6i only requires 4 exams, whereas the others require 5.

Good luck!