Only Polylines differ between the Openmtbmap and the Velomap. You can see here "what you are missing" when using the Velomap. But keep in mind, simplicity is often more important than knowing everything about a way, which is only for hardcore Mountainbikers or Hikers anyhow. While the VeloMap.org aims to show you everything you need to know for cycling as commuting, race cycling or trekking/touring - the Openmtbmap shows you more or less everything possible.
Explanation: There are 6 layouts in total. Colorwise however "thin", "wide" "clas" are all the same. Easy and Hiking are only slightly different. They only differ in the width of the lines to best match the different GPS. The mapsource/Qlandkarte GT layout (referred to as "trad" from now on) however has different colors, with less contrast. Therefore in this mag legend for Polylines (Highways) there are always two examples. One using the "trad" layout (on the top), and one using the "clas" layout below).
Please note, as this question often pops up, many variables like tracktype are just munged together from other keys like smoothness or surface. If you want to know what is the primary factor please read the sourcecode of the style-file (see FAQ).
Ways with mtb attributes or sac_scale (clickable thumbnails for full size)
Additional ways and lines (clickable thumbnails for full size)