There are afew other things though, like the speed, direction & info panels can be retracted or you can make them see thru so you get the data overlaid on the map underneath and thereby get a larger screen area.
Much faster on the redraw, drag & drop touch screen, Compact flash memory so cheap large memory capacity, much better Find tool, and a true invert function for routes, altogether a much improved unit, if you were going to have one or the other you would be foolish not to choose the 2610, but wait a bit 'cos the bike mounts are not yet sorted out.
But if you already have an SP3 then you would probably stick with that.