Artscroll tends to be the status quo for many Jewish religious texts. I can't give a reason as to why that is, but Artscroll tends to be the standard in most Orthodox religious institutions. They make up the bulk of every collection within the various Shuls and centers I've been to.
That being said, I have seen a popular uprising with a book called the Koren Sacks Siddur. This is a recent release (around 2009) which has been pretty revolutionary in that it includes a series of new prayers for women (both for mothers after the birth of children and for fathers after the birth of their daughters) and also includes a series of prayers meant to be used within the State of Israel.
I was curious if anyone who has had experience with both books would be able to give me their feedback. Are they both considered equally valid and equally accessible to Jews looking to keep observance, or is one considered "more trusted" than the other?