I have the 9″ model in that series and I like the lathe. My machine shop is in an upstairs spare bedroom and I did not feel that I could get a larger lathe into the room. My first choice would have been a 15″ lathe. My personal opinion of an engine lathe is that it is a brute part cruncher and does not offer a lot of feel. This is true on the small engine lathes as well as the large engine lathes. When a part such as a bolt needs to be made, the engine lathe is my lathe of choice. It has sufficient torque delivered to the spindle to quickly remove metal. The back gears allow you to cut a variety of thread pitches. By grinding the cutters into different forms you can cut standard 60 degree threads, acme threads, square threads, butress threads or whatever you want to cut.
That said, why would I want to use a watchmaker lathe for watch parts. There are two answers (personal opinions) to this. The first answer is they offer almost unsuparssed accuracy. This is not as crucial for larger clock parts but can be devistating to a tiny watch part. If the spindle has a runout of .001 inches and the pivot is .004 inches (.1mm) then the pivot is going to be out of concentricity by 25% of the of the shaft (pivot) diameter. The second reason is not as obvious but is also important. Because of the mass and the turning gears in an engine lathe, vibrations are transferred to the part being machined. These vibrations are transferred into the part and affect surface finish. Watchmaker lathes do not use gears and this problem is completely eliminated.