There's no preference for admissions purposes nominally, although if you're not doing A-level or AS level Maths or English you might end up not technically meeting some matriculation requirements (although I'm not sure to what extent those apply to international students), whereas with IB you'll necessarily meet that (i.e.you don't need to do math through calculus but many college seem to expect 3 or 4 years of high school math, which although in terms of topics I think you cover the majority if not all of the standard 3 year US algebra-geometry-trigonometry sequence in GCSE Maths, algebra II/precalculus for the 3rd/4th year would normally be covered in the first year of A-level here though I think; similar principles might apply to English I think?). Likewise you'll ensure you meet any (modern foreign) language requirements if you do IB and continue with a GCSE language (and even with an ab initio language and nothing at GCSE would probably still meet them).
So in a sense IB might make things slightly more convenient. It's also probably more reflective of the format of higher education in the US where you'll necessarily be taking a "mix" of subjects at least in the first two years as you tick off all the gen ed requirements for your degree while starting off your major classes and prerequisites.
However as stated there isn't going to be someone saying "this person did IB instead of A-levels/vice versa, so we will/will not admit them for that reason".
You might get more advanced placement/credit doing IB than A-level at some colleges in the US also, for whatever that's worth.