The main thing Ext.2 Math requires is just constant effort, so if you're willing to do a little bit each day - keep it.
It'll make things a lot easier for 3U, too,
Agreed, Jacaranda is pretty good.
While it may not have /that/ many questions (but it still has enough, imo), it does not skim over syllabus dot points, unlike other textbooks I have used.