With respect to doing IGETC or not:
A. If you are also considering CSUs, you probably want to do IGETC. Note that IGETC for CSU also requires oral communication but does not require foreign language that IGETC for UC does.
B. If you are only applying to UCs, you may want to look at the lower division GE requirements of each and see if you can build a selection of GE courses before transfer that require fewer courses than IGETC but satisfy all or most of the UCs’ lower division GEs.
C. Some ways of fulfilling English composition (e.g. AP English score of 3) or foreign language (e.g. high school language to a certain level) that may be accepted by your community college’s IGETC may not be sufficient to satisfy those requirements at UCs if you transfer without IGETC.
D. Note that UCB College of Engineering does not accept IGETC. For that, be sure to take at least two humanities and/or social studies courses beyond English composition while at community college, so that you only need the two upper division humanities and/or social studies courses after transfer.