I have an 8' rhino 3 pt and 15' JD batwing pull type. As you are probably aware, the pull type just can't make near as sharp as turns and more trouble to back up, even if it has CV type u-joints. If you watch a pull type turn, it doesn't seem to bad. If your sitting in the cab and doing the turn, it seems to take forever. Wear on the pto shaft and u joints is probably higher with pull type.
You mentioned semi-mounted. I assume you mean 3 pt with hydraulic lift on the rear mower wheels. Or do you mean all 3 pt lift? If you have the lift capability and enough front end weight, I would go with the semi-mounted. A big semi-mounted mower could "wag the dog" if the tractor is not big enough. Mid sized and larger utility tractor should be enough. In tight areas, frequent turns or backing up, the semi-mount wins everytime. My 8' 3 pt will beat the 15' pull type batwing in those conditions everyday.
In my area, it is really rare to see a 3 pt 10' mower. Usually 8' 3 pt or 15' batwings. I can see the usefulness of a 10' 3p but my guess is the cost is probably getting near the price of more common 15' batwing and the batwing gives 50% more coverage, less scalping and follows the contour better.
