Is ABSM similar to RCM? We have 10 grades, then ARCTs. The music selection is similar, with some baroque/classical, some romantic, and some modern/jazz. I wonder if the difficulty is comparable.
Ah, sorry. ABRSM (associated Board of the Royal School of Music) is the daddy of them all, exam-wise, and is used all over the world, though obviously based in Britain. There are other boards here - Guildhall, Trinity - but for yer basic piano exam there's no point in doing anything other than ABRSM, which is what most UK players have been brought up on for decades (my grandmother remembered having John Ireland as examiner for her ABRSM Grade 5; my own pupils had Kevin Bowyer a year or so ago).
There are 8 standard Grades (marked out of 150 - 100 for a pass, 120 for a 'Merit', 130 for a 'Distinction') plus at the low end a preparatory test and at the top end various advanced diplomas, of which the final one (the FRSM) features, at its hardest end, pieces like the Boulez
First Sonata,
Gaspard de la nuit etc.
The 8 Grades, as I said, ask you to choose three pieces, one Baroque/Classical, one Romantic, one Modern. Grade 8 is slightly different in that the first piece is specifically contrapuntal, to test your clarity and general part-playing skills (therefore not necessarily Baroque), and the second is a Sonata, to test sense of structure etc., I suppose (therefore not necessarily Classical or Romantic). If you're so inclined - as I was - you can play all 20th century for your Grade 8, then: mine was a Prelude and Fugue from
Ludus Tonalis (Hindemith), the Janacek
Sonata and a Rachmaninov
Prelude.
I think it's fair to say that pieces are getting easier as time goes on. I'm almost sure that pieces which were set for Grade 1 a few decades back are now being set for Grade 2, though don't quote me on it because I can't remember which pieces I'm talking about.

At the same time, it is often said that Grade 8 used to be sufficient to get you into a Music College; now it's pretty common and not such an acheivement as it once was, though still laudable of course - you need more if you want to take your music performance in a more professional direction.