Hey Colludium.
First I tried with an ipad2. Perfectly smooth right from the start (may have dropped to 59 fps at one point but didn't cause it to jank).
Next on the desktop, loaded it up in chrome and surprisingly - for the first 10 seconds or so it was pretty janky - then perfectly smooth (of note, every time I load it up again in chrome now it is perfectly smooth from start to finish). Tried in firefox, jank for about 2 seconds then perfectly smooth (same story subsequent attempts are perfectly smooth from the start). Not sure what that is about.
Will try again with a couple more devices later and update.
(old i7, gtx 660)