All folded scopes have a compromise. For the same eypiece fold outside the tube, two mirror Newts have a lesser obstruction than three mirror folds but th eyepice points up at typically 45 degrees. The problem with all folded scopes is in th ebaffling.
Heres a link to Dan Grays folded 28". Gives you an idea of complexity in baffling the secondary mirror.
http://www.siderealtechnology.com/28inch/
Mark