It is better than (most) Protestant study Bibles in the NT, except for one thing: maps (and color). The maps suck. The content itself is excellent and multitudinous, and cross-referenced with the CCC and other references so one can look up even more footnotes. The only Protestant study Bible I would say that is in the same league as terms of the quality of annotations is the Lutheran Study Bible published by Concordia (LCMS: which is likely better than the ICSB-NT - except it doesn’t give the fully-Catholic point of view, but a very conservative and historical Lutheran one, which is similar to Catholicism - it is likely more comparable to Haydock, as, on the first page alone, Genesis 1:1-7 or something, the Church Fathers are quoted - verbatim, and with citations to ANF and NPNF, etc.! - no less than eleven times!).
My favorite actual study Bible is the Haydock, which is published in full Folio size (roughly 16x12 inches), and has, at an estimate, probably ten volumes of actual commentary in it. (It is translated from the Vulgate, so it has all of the advantages and disadvantages that thereto accumulate.) Beyond those two, no other Catholic study Bibles can really come close, except, for the NT, the three-volume Navarre (which, due to formatting, probably has less annotation than either of the above). The OT of the Navarre in seven volumes, has good annotation but is based on a poor translation (the original RSV-CE), so it I rarely recommend.
I have an ESV study Bible, and, to me, the notes are kind of bland, especially in the OT (just general historical notes, although from a somewhat conservative perspective), and are bland in several ways in the NT (in regards to areas that are contested amongst evangelicals, such as dispensations and the millennium), but at least in the NT they take an identifiable Reformed or Reformed Baptist stance, with notes militating against baptismal regeneration, etc. The binding on the ESV study Bible is terrible, as the pages are folded cross-grain so one gets them standing up straight and “crinkling” down the gutter.
My personal preference is for a text-only with cross-references Bible, generally in the King James Version (although I do use a few others), to be used with separate volumes of commentary, generally of the ancient Church Fathers. (I recently took a second look at the Ancient Christian Commentary series edited by Thomas Oden, and it is growing on me, unlike the first time I used it, although neither the Church Fathers nor the ACCS has displaced the Brazos Theological Commentary as my main resource as of yet.)
If you are wondering whether to buy the ICSB-NT, most certainly do so. It is one of the top five study Bibles made. I don’t know when they’ll complete the OT, and doubt it will be published in one volume, but, I read the notes on Genesis in the multiple-volume ICSB-OT release, and, as a strict six-calendar-day creationist, found them frankly dishonest, full of rhetorical sleight-of-hand (of course, many Bibles just dodge the Gen 1-2 questions altogether, and don’t annotate on it, or annotate it with some fact of God’s universe) mildly offensive, so I’m not sure I’d buy the OT, especially as it is not in one of my preferred translations.
However, the RSV-2CE NT is excellent, and, combined with Scott Hahn’s notes, is an excellent study Bible - it’s close to as good as a study Bible can be, realizing that 1) it has poor maps and no color, and 2) any study Bible, no matter how good, can only scratch the surface of commentary (with a partial exception for Haydock’s NT, as the notes are so small in font and the pages so large).
The OP is correct about Catholic Bibles, though. By and large, they suck. The situation for Catholic study Bibles is even worse. I’ll only use the RSV-2CE NT (with a Greek TR to fill in the blanks), the Haydock/Douay-Rheims, and, holding my nose, an RSV-2CE OT. We only have two or three decent study Bibles (and only one, being generous, that combines a good translation and good notes and is on the whole Bible), and the only one that’s below $120 (and that’s for a hardcover covered in bonded leather) is NT only. The Navarre is $450. Our other Bibles - the New American, the New Revised, the New Jerusalem, the Little Rock Bible, the Christian Community Bible - are heretical to apostatical, and unbelieving, not to mention very bad translations. And we have no Bibles that come in decent, calf or goatskin bindings, smyth-sewn. Just because a Protestant points it out, does not mean it is not true; there is a reason why I use the KJV most of all (because one can buy editions, such as the NCPB and Cameo, that include the Catholic books), and then, following it up, NKJV, DRC, NASB, and OSB - only one of those is a Catholic Bible, and it gets the least use of all (it’s poorly formatted and, disregarding the format, is lacking euphony, but is nigh-impeccably doctrinally correct, disregarding a few corruptions in the NT such as 1 Tim 3:16 “quod”]), and is used mainly because of how good Haydock’s notes are, which come only in the DRC version.
The Oxford Catholic Study Bible is based on the aforementioned NAB, and, as the OP pointed out, is utter garbage, except possibly for use in learning the latest secular theories of the Bible in order to refute them - it’s not even fitted to classroom use, as universities use the NRSV in the New Oxford Annotated Bible variety, which, again, is useful insofar as Sun Tzu’s maxim to know thy enemy applies (and the reader has a strong faith and is not easily shaken by contrary winds).