You can cut square with the Bosch if you use a separate square instead of the stops that build in the saw! You can see the problem of the bending baseplate in the Bosch video, this causes the problem of geting a corect angle by the stops also! You have time consuming adjusting work if you want a good 90/45° cut!
The Mafell and the old TS55(also the new R-model since 2015) have two stops for each angel ans the Festool got a stiffer baseplate so you don´t have any problems with that!
If you using a Mafell or Bosch on a Festool guiderail it only reach over one of the two glidestripes so it tilts and you don´t get a 90° (or what ever angle you want) cut!
If you use a Festool rail with a Bosch or Mafell saw the saw blade pivot point is lower than the edge of the rail, so the cut ist at 45° not at the railedge and you lose this feature.
I think we was 6 people at the german forum that got the Bosch for testing and nearly (?) everyone has adjust the saw because the stops were more than 1,5° of!