My DD did Further Math HL last year and it was a good fit for her mathematically. Since this was the first year for the test, it was quite difficult to get information on what to study. No textbooks that we could find (although you could make a start by looking at Mathematics HL and studying all the sections). No practice tests seemed to be available. Unlike many other IB math classes, it did not have a portfolio or "writing" component. Instead, it seemed to be just the teacher evaluation and the end of course tests. It may be different once this course is better established. My DD reports that it was substantially harder than the practice (old) Further Math SL or Mathematics HL tests that she saw and some things that HL tested on were not in the old SL textbook. This is to be expected since linear algebra was added.

As to colleges, none of the colleges DD is looking at currently lists a credit for Further math HL. Many do discuss contacting the math department directly for information on course credit for IB and AP and have information on math placement tests.

Many of the IB students here take the corresponding AP tests in addition to the IB tests.
May is a bad month here.