In my experience a Sp is quicker than a trailed, forward speed is quicker due to larger web area, no stopping at ends, quicker at lifting short ground and the trickier the conditions get the advantages of running a sp become transparent
Probably so. ime an sp on big wheels ground to a halt before my trailed. They have a very similar seperation area - in kind dry conditions, we regularly top 10kph with our T2 - an sp isn't going to beat that by much. (We've been tapping on at 5kph this last week) They need to make some savings re very short garings etc, they're double the money of a trailed machine. Some need the field opening up for them. None that I'm aware of can windrow in the absence of a trailer.
Swings and roundabouts I guess.